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Obstetric Vasculopathies
First Edition: 2013
9789351527817
Printed at
The interpretation of a pediatric chest radiograph might appear challenging, but understanding the effect of technical factors and age; and a systematic approach can help us to reach a correct diagnosis.
- Check patient particulars and the side marker
- Note the projection (AP/PA)
- Note the phase of respiration
- Verify the presence of rotation
- Note the presence of artifacts, if any
- Systematic review of all the structures for abnormalities
- Suggest a diagnosis based on the radiograph and never forget to review the clinical background.
Effect of age
In a child:
- The anteroposterior diameter of the chest is usually more
- Air bronchogram frequently seen projected in the retrocardiac location in the neonate and young infant (Fig. 1.1)
- If seen more peripherally, considered pathological
- Anterior aspects of the diaphragms usually are at a higher level and the lower zones may be obscured.
Thymus
- Prominent anterior mediastinal shadow with the characteristic ‘Sail sign’ (Fig. 1.2)
- Gradually disappears at around 7–8 years of age
- Can appear very prominent in some infants and must be differentiated from a mediastinal mass or consolidation (Figs 1.3A and B)2
Figs 1.3A and B: Normal thymus mimicking anterior mediastinal mass. (A) Supine chest radiograph shows widened superior mediastinal contour, with asymmetric bulge on the right side. (B) CECT chest shows a homogeneous hypodense lesion in anterior mediastinum.
- Wavy contour (due to ribs) is helpful and sometimes a lateral projection might be of benefit
- Ultrasound shows a characteristic “starry sky appearance”.
Technical pearls
- As babies and most toddlers are imaged by an AP radiograph, do not forget about cardiac magnification
- Pleural effusion can give the appearance of increased opacity of a hemithorax, on a supine X-ray (Fig. 1.4)
- Expiratory phase (Fig. 1.5) film shows an apparent enlargement of the heart size and prominent bronchovascular markings (in a normal inspiratory film anterior end of 6th rib should be visible above the diaphragm)
- Rotation is the most common cause for unilateral increased or decreased translucency
- Skin folds may mimic pneumothorax (Figs 1.6A to C)
- On an oblique or rotated radiograph, sternal ossification centers may mimic lung nodules.
Figs 1.6A to C: (A) Skin fold mimicking left pneumothorax on a chest radiograph (arrow); (B) the child had a lipoma on the back which shows hyperintense signal on T2WI, and (C) loss of signal on T2W fat suppressed images.
Interpretation of Abnormal Radiological Signs
Radiographic abnormalities should be interpreted after consideration of the age, clinical history, examination findings, laboratory investigation and previous imaging reports, if available.
Systematic Review
Mediastinum
- Loss of visualization of the aortic knuckle indicates that the mass lies in posterior mediastinum (adjacent to the aortic arch) (Figs 1.9A to C).
- Lateral deviation of the trachea indicates a middle mediastinal mass, (e.g. bronchogenic cyst, lymph nodes).
- Posterior mediastinal mass (e.g. neurogenic tumor) may result in pressure erosion or splaying of the posterior rib ends (Figs 1.10A and B).
- Acute infection or steroid therapy may cause transient thymic atrophy. However, the possibility of an absent thymus gland must be considered (Di George syndrome) if it is persistently small.
- Rebound thymic hyperplasia and anterior mediastinal tumors may be difficult to differentiate on imaging.
Figs 1.7A and B: Mediastinal mass silhouetting the right heart border on chest radiograph (A) and axial CECT image (B) showing bulky lymph nodal mass in anterior mediastinum.
Figs 1.8A and B: Anterior mediastinal dermoid cyst. (A) Chest radiograph shows a mass obscuring the right cardiac border. (B) CECT chest axial image shows a cystic anterior mediastinal mass with peripheral rim calcification.
Figs 1.9A to C: Posterior mediastinal mass (neuroenteric cyst). CT scout image shows non-visualization of the aortic knuckle. (B) Axial CECT of chest shows a cystic lesion in posterior mediastinum. (C) Volume rendered images show vertebral segmentation anomalies in upper dorsal vertebrae.
Figs 1.10A and B: Posterior mediastinal ganglioneuroma. (A) Chest radiograph shows a large mass in posterior mediastinum causing obscuration of the margin of aortic knuckle, and splaying of the left 4th and 5th ribs, notching of the left 4th rib undersurface posteriorly (arrow). (B) CECT chest axial image shows large posterior mediastinal mass with calcification.
Heart and Great Vessels
- Normal cardiothoracic ratio is 60% in infants
- Establish situs by inspection of the bronchial anatomy, gastric bubble, the ascending and descending aorta
- Right-sided aortic arch is associated with various congenital heart diseases
- Closely inspect lungs to assess pulmonary vascularity in any case with cardiomegaly
- Visible pulmonary arterial branches in the periphery of the lung, suggests pulmonary plethora (increased blood flow)
- Non-visualization of the central pulmonary vessels suggests reduced pulmonary blood flow.
- On chest radiograph, imaging pointers of pulmonary arterial hypertension include peripheral pruning of the pulmonary arteries and enlarged central pulmonary arteries.
While abnormalities in cardiac contour may be useful to diagnose the anatomical cardiac chamber enlargement, the causes of chamber enlargement are wide and nonspecific; which requires full assessment by echocardiography.
Lungs and Pleural Cavities
Bilateral Increased Translucency (Figs 1.11A and B)
Generalized increased translucency of the thorax:
- Large inspiratory effort
- Airway diseases (asthma, bronchiolitis and cystic fibrosis)
- Upper airway obstruction due to tracheal obstruction (e.g. vascular ring or tracheal foreign body).
- Patient rotation, probably the most common cause
- Which side is abnormal
- Pulmonary vascularity
- The side with decreased vascularity is usually abnormal.
- The side with increased or normal vascularity is normal.
- Changes in appearance between inspiratory and expiratory films
- The side which shows least change on expiration is usually abnormal.
- Size of the hemithorax
- A small opaque hemithorax is usually abnormal.
- Obstructive emphysema
- Attenuated pulmonary vessels
- Expiratory film will exaggerate disparity between normal and abnormal lung
Figs 1.11A and B: (A) Chest radiograph and (B) CT lung window show generalized hyperinflation and increased translucency of the lung fields.
Figs 1.12A to C: Pulmonary hypoplasia. (A) Chest radiograph shows small hyperlucent left hemithorax, with eventration of left hemidiaphragm. (B) Axial CECT chest mediastinal window and (C) lung window reveal small left pulmonary artery and hyperlucent lung field.
- Compensatory emphysema
- Less marked on expiration
- Pulmonary hypoplasia (Figs 1.12A to C)
- Small hyperlucent lung
- Small calibre of pulmonary artery
- Swyer-James-Mcleod syndrome
- Acquired bronchiolitis obliterans
- Small lung with hyperlucency
- Air trapping and small calibre of pulmonary artery
- Chest wall causes Poland syndrome (Figs 1.13A and B).
Pneumothorax (Fig. 1.14)
- Increased translucency of the hemothorax
- Visualization of the lung margin
- Anterior loculation of the pneumothorax may be indicated by the only abnormality of increased clarity of the heart border.
Pneumomediastinum
-
Figs 1.13A and B: (A) Poland syndrome. Increased translucency of right hemithorax. (B) Axial NCCT of chest shows absent pectoralis muscles on right side.
- Increased clarity of the cardiac outline
- Air outlines the lobes of the thymus.
Increased Pulmonary Opacification
- Pulmonary infiltrates:
- Air space opacities: Air bronchograms; consolidation may be segmental or lobar in distribution (Figs 1.15A to C)
- Pulmonary edema, bronchopneumonia, aspiration changes are usually bilateral.
- Interstitial infiltrates:
- Linear pattern with peribronchial thickening—acute interstitial pulmonary edema or infection (e.g. viral bronchiolitis)
- Chronic interstitial disease—reticulonodular, nodular, miliary opacities and a honeycomb appearance (Fig. 1.16)
-
Figs 1.15A to C: Consolidation in two different patients. CT scout image (A) and CT lung window image (B) showing consolidation with air bronchogram in bacterial pneumonia. Chest radiograph (C) in another patient showing right upper lung zone consolidation with air bronchogram.Fig. 1.16: Reticulonodular shadows in a case of interstitial lung disease in Langerhan's cell histiocytosis.Fig. 1.17: Right middle and lower lobe collapse. (A) There is increased opacity of right lower lung zone with obscuration of the right cardiac border and right hemidiaphragm. Another patient with opaque right hemithorax (B) shows a metallic foreign body (C) on axial CT image.12Fig. 1.18: Complete collapse and destroyed left lung leading to increased opacity of left hemithorax.
- Pulmonary aplasia and agenesis
- Small lung volume with increased opacity
- Pleural fluid
- In supine position
- Large pulmonary/chest wall mass
- Diffuse pleural thickening.
Pulmonary Nodules
- Wide differential diagnosis
- Most common cause in childhood is ‘round pneumonia’
- Multifocal nodules are most commonly infective [septic emboli, miliary nodules (Fig. 1.19)], metastases.
- Solitary nodules can be infective (granuloma, round pneumonia), hamartoma (Fig. 1.20) or metastasis.
- Pulmonary masses (described in separate chapter 13).
Fig. 1.19: Miliary tuberculosis. Chest radiograph showing fine nodules of uniform size scattered in both the lung fields.
Ring Shadows (Figs 1.21A and B)
Ring shadows refer to air-filled cystic lesions with thin wall
- Bronchiectasis
- Cystic fibrosis
- Pneumatoceles—staphylococcal and streptococcal pneumonia
- Bronchogenic cyst
- Congenital diaphragmatic hernia
- Cystic adenomatoid malformation
- Bronchopulmonary dysplasia.
- Normal position:
- Right hemidiaphragm can normally be higher than left
- Difference of height >1.5 cm between the two hemidiaphragms abnormal
- Marked elevation:
- Loss of lung volume
- Diaphragmatic paralysis
- Eventration
- Congenital diaphragmatic hernia
- Subpulmonary effusion.
- A flattened diaphragm:
- Indicates overinflation
- Loculated subpulmonary pneumothorax.
Thoracic Skeleton and Soft Tissues
Discussed in the Chapter 9.
Figs 1.21A and B: Ring shadows in cystic bronchiectasis. (A) Chest radiograph showing ring shadows and nodules in right lower zone; (B) CT shows cystic bronchiectasis.
Chest radiography is the usual initial imaging modality, followed by CT when necessary.
Ultrasound is helpful in the evaluation of:
- Persistent/unusual opacity in the peripheral lung on chest radiography
- Pleural pathologies
- Mediastinal widening on chest radiograph
- Completely opaque hemithorax
- Useful in image-guided interventions (biopsy or pleural fluid drainage).
Technique
Transducers
- Neonates and infants—high resolution 5–10 MHz linear-array transducer
- Children and adolescents—2–4 or 4–7 MHz sector or linear-array transducer.
Approaches
- Guided by a prior radiograph to focus on probable area of abnormality
- Trans-sternal, parasternal, and intercostal approaches—for the lung, pleura, anterior mediastinum
- Sector transducers useful in subxiphoid and transdiaphragmatic approaches—juxtaphrenic paravertebral lesions
Normal chest sonography
- B lines: Vertical lines intersecting the ‘A’ lines, ‘comet-tail artifacts’ (Fig. 2.3)
- 3–4 can be normally seen
- If more in number, indicate in alveolar or septal infiltrates (e.g. transient tachypnea of the newborn, Figs 2.4A to C)
Fig. 2.1: Normal chest sonogram on a linear transducer. The parietal pleura is seen as an echogenic line (arrow). ‘A’ lines are the horizontal lines parallel to it (small arrows), indicating the presence of air underneath. When seen in conjunction with sliding pleura sign, it is considered normal.Fig. 2.2: Normal chest sonogram on a curvilinear transducer. The parietal pleura is seen as an echogenic line (arrow). ‘A’ lines are the horizontal lines parallel to it (small arrows).Figs 2.4A to C: Transient tachypnea of the newborn in a term neonate. Chest radiograph (A) showed opaque hemithorax involving the right lower zone with air bronchogram. Chest sonography (B) revealed presence of multiple B lines (arrow). Follow-up radiograph (C) after 48 hours showed complete clearing of the lung infiltrates. - Hyaline membrane disease/respiratory distress syndrome (Figs 2.5A and B):
- Whiteout lung on chest radiograph
- Retrodiaphragmatic dense echogenic shadow
Pleural Diseases
- Ideal for imaging with Ultrasound
- Differentiates pleural fluid from peripheral pulmonary consolidation
- Pleural fluid aspiration/localization (Figures 2.6 and 2.7) (also refer chapter 10)
- Normal pleura shows ‘sliding pleura sign’ on B-mode and seashore sign on M-mode sonography (Fig. 2.8)
- Sliding pleura sign-Defined as dynamic horizontal to and fro movement of pleural line during respiration
- Seashore sign- Ground-glass or sandy appearance under the pleural line indicating normal lung tissue
- Absence of sliding pleura sign and ‘barcode sign/stratosphere sign’ suggests pneumothorax (Fig. 2.9)
- Barcode sign- Absence of normal ‘Seashore sign’ below the pleural line, replaced with multiple small horizontal linens indicating pneumothorax
- US can demonstrate the cause of elevated hemidiaphragm on radiographs.
Fig. 2.6: Free pleural effusion seen as anechoic clear fluid in the pleural space. The diaphragm is shown with an arrow.
Figs 2.7A and B: US images of empyema, showing thick echogenic pleura (arrow), septations and internal mobile echogenic debris (short arrow).
Parenchymal Lesions
Consolidation and Atelectasis
- Airless lung looks similar to echotexture of the liver and spleen
- Multiple bright dotlike and branching linear structures—sonographic air bronchogram
- Consolidation—lung volume is not decreased and bronchi show normal branching pattern
- Atelectasis—decreased lung volume and of the involved lung can be crowded
- Passive atelectasis—air bronchogram present as long as bronchi are patent
- Mucoid impaction—bronchial tree is filled with fluid (replacing normal air), sonographic fluid or mucus bronchogram
- Color Doppler US shows the presence of normal branching pattern of pulmonary vessels in consolidation.
Mediastinal Masses
- Mainly as a screening tool for equivocal findings
- CT or MRI for definitive diagnosis
- Young children with superior mediastinal widening
- Helpful in differentiating normal thymus from mediastinal masses
- Children less than 1 year old provide an excellent acoustic window, as the sternal ossification centers are not fused.
Normal Thymus
- Variable size
- Homogeneous, finely granular echotexture; shows echogenic strands (Figs 2.10A and B).
Abnormal Thymus (Figs 2.11A and B)
- Heterogeneous echogenicity
- Coarse echotexture
- Calcifications.
Figs 2.10A and B: Transverse sonogram (A) and CT sagittal reformatted image (B) of the mediastinum shows the normal appearance of the thymus in a child. The normal thymus is shown with an arrow.
Figs 2.11A and B: Anterior mediastinal mass (immature germ cell tumor) in a 15 month old girl. Chest radiograph shows (A) anterior mediastinal mass, which is heterogeneous in echotexture on ultrasonography (B).
Other Mediastinal Masses
- Chest radiography—localizes masses into anterior, middle, or posterior mediastinum
- Role of US remains in the characterization of a mass as solid or fluid filled and detection of calcifications.
We acknowledge the contribution of Dr Krithika Rangarajan to this chapter.
Causes
- Pulmonary
- Medical
- Surgical.
- Extrapulmonary
- Cardiac
- Pleural (discussed in respective chapter)
- Diaphragmatic
- Airway obstruction
- Neuromuscular causes.
Imaging Modalities
- Chest radiograph—primary imaging modality
- CT in surgical conditions with equivocal findings
- Ultrasound (also see Chapter 2).
Pulmonary—Medical Conditions
- Transient tachypnea of the newborn (TTN), Wet-lung syndrome
- Hyaline membrane disease (HMD), respiratory distress syndrome (RDS)
- Meconium aspiration syndrome
- Neonatal pnuemonia
Transient Tachypnea of the Newborn (TTN; Figs 3.1A and B)
- Fluid is actively secreted in the fetal lung. At birth cleared through peribronchial lymphatics and veins. Extravolumes of fluid produce temporary distention and congestion.
- Predisposing factors: Cesarean section, prematurity, hypoproteinemia, hyponatremia, maternal diabetes and maternal fluid overload.
- Presentation: Peak respiratory distress on the day one of life (as early as 2 to 4 hours of age). Progressive improvement and most babies asymptomatic by 48 hours.
- Chest radiograph: Symmetrical parahilar radiating congestion, mild-to-moderate lung over aeration.
- Differential diagnosis: Vascular congestion.
- Hallmark: Transient clinical and radiographic course.
- Lack of surfactant, immature lungs. Collapse of small alveoli but larger alveoli and terminal bronchioles are overdistended. Later there is transudation of proteinaceous material into alveolar space with formation of classical hyaline membrane
- Clinical presentation: Hypoxia. Respiratory distress in the first few hours of life, worsens during first 18-24 hours. Improvement begins by the third day
- Chest radiograph: Under aerated lungs, finely granular, air bronchogram.
Figs 3.1A and B: Transient tachypnea of newborn in a term neonate. Chest radiograph on day one of life (A) revealed uniform opacification of bilateral lung fields, air bronchograms within (arrow) and increased lung volume. Subsequent chest radiograph one day later (B) revealed significant clearance of the lung opacities.
Figs 3.2A and B: Hyaline membrane disease. Chest radiographs of two different preterm neonates show bilateral under aerated lungs with reticulonodular opacities and air bronchograms, changes typical of HMD.
Figs 3.3A and B: Hyaline membrane disease in a preterm neonate with respiratory distress. Chest radiograph at birth (A) shows opaque bilateral hemithoraces having fine granular appearance, and small lung volume. Chest radiograph after 4 days of surfactant replacement therapy revealed significant improvement (B).
Meconium Aspiration Syndrome (MAS; Figs 3.4A and B)
- Term or post-term babies. Complication of fetal distress—fetal gasping and in utero passage of meconium.
- Clinical presentation: Severe tachypnea with profound hypoxia. Respiratory distress almost immediately after birth.
- Chest radiograph: Findings depend on severity of the aspiration and ratio of amniotic fluid to meconium and include over aeration, bilateral streaky densities, focal emphysema, consolidation and pleural effusion.
- Rapid clearance seen in amniotic fluid aspiration, slow in meconium aspiration.
Figs 3.4A and B: Meconium aspiration. Chest radiographs of two different term neonates showing radiographic changes typical of MAS. Figure (A) demonstrates focal emphysema of right lower zone with consolidation of right upper lobe with loss of left lung volume. Figure (B) shows collapse of right upper lobe with consolidation of left middle and lower zones and pleural effusion.
- Preterm or premature rupture of membranes predispose.
- Ascending infection from vagina, perineum, less common— transplacental.
- Infections occur during passage through the birth canal or soon after birth.
- Chest radiograph: Great mimicker-varied manifestations. Lung volumes—normal/increased, asymmetric consolidation, streaky opacities or nodules and pleural effusion.
Figs 3.5A and B: Neonatal pneumonia. Sequential chest radiographs of a four-day old neonate presenting with poor feeding and fast breathing, reveal multiple areas of consolidation involving right upper and middle zones and left retrocardiac location (A). Repeat radiograph at day 14 of life reveals almost complete resolution with in-hospital antibiotic treatment (B).
Figs 3.6A to C: Neonatal interstitial pneumonia in a preterm child with respiratory distress. Chest radiograph at hospital admission shows extensive consolidation in right lung with right pneumothorax. The pneumothorax was drained by an intercostal tube. Radiographs taken after 2 days (B) and 4 days (C) of in-hospital treatment show no significant improvement in the right lung consolidation and development of consolidation in left lung also.
Differentiating Features
- Gestational age
- Preterm—HMD
- Perm/post-term—TTN, MAS
- Time of onset/progression—TTN earliest, pulmonary edema—after 24 hours
- Lung volumes
- Small-HMD
- Large-TTN, MAS
- Asymmetry—pneumonia
- Pleural effusion—unusual in HMD, seen in pneumonia/MAS.
Therapy
Complications of Therapy
- Early: Pulmonary hemorrhage, air leak
- Late: Bronchopulmonary dysplasia, Wilson-Mikity syndrome
Pulmonary Hemorrhage (Fig. 3.7)
- In conditions with severe hypoxia—HMD, pneumonia or aspiration.
- Vitamin K deficiency, thrombocytopenia or DIC
- Surfactant therapy
- Clinical presentation: Suspect if clinical deterioration while on therapy, poor prognosis.
- Chest radiograph: If severe causes complete opacification of lungs, air bronchogram present.
Complications of Ventilation
Early-Air leaks
- Pulmonary interstitial emphysema (PIE): Rupture of alveoli with escape of air into interstitium—dissects along the bronchovascular sheaths to the periphery of the lung —causes pneumothorax, pneumomediastinum.
Late
- Bronchopulmonary dysplasia (Chronic lung disease of infancy; Figs 3.8A to C)
- In babies with HMD placed on oxygen and positive pressure ventilation. Definition—oxygen dependence with abnormal chest X-ray at 28 days of age.Fig. 3.7: Pulmonary hemorrhage. Chest radiograph of a two-week-old neonate shows diffuse opacification of bilateral lungs. HMD is excluded as the neonate was a full-term delivery and the child was normal at birth. Pulmonary hemorrhage was suspected in this child.Figs 3.8A to C: Bronchopulmonary dysplasia (BPD). Sequential chest radiographs of a preterm infant at day 20 (A), 29 (B) and 40 (C). The child was put on mechanical ventilation for respiratory distress and remained oxygen dependent at 4 weeks. The sequential radiographs show hyperinflation with areas of reticular opacities suggestive of fibrosis. Oxygen dependence at 28 days with variable combination of overinflation and fibrosis are suggestive of BPD.
- Effect of trauma on immature lungs. Alveolar damage-fibrosis interspersed with emphysematous changes.
- Chest radiograph: Hyperinflation—generalized or patchy, emphysematous, bullous or cystic changes, linear streaks. Cysts more in lung bases. Later-pulmonary artery hypertension.
- CT: Parenchymal bands, areas of decreased attenuation, cystic changes. More marked anteriorly.
- Differential diagnosis: PIE.
- Wilson-Mikity syndrome
- In premature infants who may receive oxygen therapy but no positive pressure ventilation in first few days.
- Chest radiograph: Bilateral coarse, linear densities and cystic areas.
- Differential diagnosis: PIE, BPD but BPD patients have history of prior positive pressure ventilation.
Pulmonary—Surgical Conditions (also see Chapter 4)
- Congenital lobar emphysema (CLE)
- Congenital cystic adenomatoid malformation (CCAM)
- Congenital diaphragmatic hernia (CDH).
Congenital Lobar Emphysema (CLE; Figs 3.9A and B)
- Due to focal bronchial cartilage deficiency, bronchial walls collapse during expiration causing check valve bronchial obstruction and air trapping.
- Chest radiograph/CT: Typical—overdistension of a single lobe with compression of adjacent lobe. Commonest—left upper lobe. Contralateral mediastinal shift. Opaque hemithorax in the first few hours of life.
- CT: Hyperlucent distended single lobe
- Differential diagnosis: CCAM.
- Abnormal proliferation of bronchial structures with formation of a large complex, multicystic mass, which may communicate with the bronchial tree.Figs 3.9A and B: Congenital lobar emphysema. Chest radiograph of a neonate shows a large cystic lesion involving left upper zone with collapse of the adjacent parenchyma and subtle contralateral mediastinal shift (A). Axial CT (B) of another neonate in lung window shows hyperinflated left upper lobe. Collapse of left lower lobe was seen on other sections (not shown). The location and adjacent parenchymal collapse are typical of CLE.Figs 3.10A to C: CCAM. Chest radiograph (A) and axial CT images (B, C) of a neonate reveals multiple well defined small air containing cystic lesions in the superior segment of left lower lobe suggestive of type 2 CCAM.32Figs 3.11A and B: CCAM. Fetal MRI (axial and coronal TRUFISP) done to characterise cystic lung lesions at routine obstetric ultrasonography at 18 weeks show multiple small cysts involving single lung suggestive of type 2 CCAM. There were no associated malformations.
- Clinical presentation:
- Severest form: Fetal cardiac compromise due to thoracic mass, fetal hydrops and maternal hydramnios: still birth. Less severe: Neonatal respiratory distress.
- Older child: Infection/dyspnea/incidental.
- Cysts of varying sizes. Type 1: Large >2 cm, few cysts. Type 2: Smaller <2 cms more cysts. Type 3: Microcysts, numerous, apparently solid lesion. A recent classification divides them into five types, depending on cyst size.
- Chest radiograph: Complex, air containing cystic lesion, contralateral mediastinal shift. Opaque hemithorax in the first few hours.
- CT: Cysts/septae better appreciated.
- Differential diagnosis: CDH, CLE.
Congenital Diaphragmatic Hernia (CDH; Figs 3.12A to C)
- Congenital diaphragmatic defects with herniation of abdominal contents. Ipsilateral/in severe cases contralateral pulmonary hypoplasia. Vasospasm in hypoplastic lungs causes pulmonary arterial hypertension.33Figs 3.12A to C: Congenital diaphragmatic hernia. Chest radiograph (A) of a neonate presenting with respiratory distress shows multiple cystic lucencies in the right hemithorax with moderate degree of contralateral mediastinal shift. Also noted is relatively airless abdomen. These findings are diagnostic of congenital diaphragmatic hernia. Fetal MRI (HASTE sagittal and coronal sequences; A and B) of another patient done to confirm an abnormality detected on antenatal USG shows well-defined round and elongated hyperintensities (arrows) extending from the abdomen and occupying the right hemithorax causing contralateral mediastinal shift. These findings confirm the diagnosis of congenital diaphragmatic hernia with hyperintense signal representing the meconium.
- Chest radiograph: Cystic lucencies in lower hemithorax with contralateral mediastinal shift. Abnormal abdominal gas pattern. Opaque hemithorax in the first few hours.
- CT: Seldom indicated.
- Oral contrast studies: For bowel herniation.
- Differential diagnosis: CCAM.
Approach: Neonatal Respiratory Distress
Chest Radiograph
- Lung abnormality without mediastinal shift: Medical cause
- Lung abnormality with mediastinal shift: Surgical cause possible.
Cystic Lucencies with Mediastinal Push
- CCAM :Presence of cysts/septae/solid areas. Normal bowel gas pattern.
- Diaphragmatic hernia: Lower hemithorax, abnormal abdominal gas pattern
- Oral contrast/USG help.
Opaque Hemithorax with Mediastinal Push
- CLE, CCAM, CDH: If radiographed too early. Repeat radiograph after a few hours.
- Effusion/Type 3 CCAM.
- Chylothorax.
We acknowledge the contribution of Dr Pankaj Gupta to the above chapter.
Congenital lung abnormalities include a wide range of anomalies involving the lung parenchyma, bronchial tree, the arteries and the veins. They have been classified in multiple ways. Collectively, they can be termed ‘bronchopulmonary vascular malformations (BPVM)’. ‘Malinosculation’ is a new term coined to describe the anomalous communication between different components.
A more recent classification of these group of entities by Lee et al.1 (2008) divides the BPVMs systematically depending on the components affected (e.g. isolated bronchial, arterial or venous; or mixed bronchoarterial, mixed bronchovenous, mixed arteriovenous or mixed bronchoarteriovenous malinosculation). Isolated bronchial malinosculation include tracheal stenosis, bronchial atresia, cystic adenomatoid malinosculation, congenital lobar emphysema, bronchogenic cyst, etc. Isolated arterial malinosculations include pulmonary artery interruption, systemic and dual artery supply to normal lung. Isolated venous anomalies include partial and total anomalous pulmonary venous drainage, meandering pulmonary vein, scimitar variant and isolated unilateral single pulmonary vein. Previously described intralobar sequestration is termed as mixed bronchoarterial malinosculation in the new classification. Classical Scimitar syndrome and extralobar sequestration can be described as mixed bronchoarteriovenous malinosculation. Pulmonary agenesis, aplasia and hypoplasia represent variable degree of maldevelopment of all the components. Variable combination and overlap of the above mentioned entities may be seen.
Developmentally, BPVMs can be classified in a more simplified manner as follows (congenital upper airway abnormalities are described separately in Chapter 7):
- Abnormal lung bud development/vascular development
- Abnormal lung bud separation
- Sequestration
- Hamartomatous lesions
- Cystic adenomatoid malformation
- Bronchogenic cyst
- Congenital lobar emphysema.
Lung Agenesis: Hypoplasia Complex
Pulmonary Agenesis
- Complete absence of lung parenchyma, bronchial tree and vascular supply (Figs 4.1A to D).
Figs 4.1A to D: Left pulmonary agenesis. CT scout film (A) reveals opaque left hemithorax with ipsilateral mediastinal shift. CECT chest axial image mediastinal window (B) and lung window image (C) shows absent left pulmonary artery and left main bronchus. Coronal reformatted lung window image (D) shows absence of left lung and left main bronchus.
Pulmonary Aplasia (Figs 4.2A to C)
- Complete absence of lung parenchyma, rudimentary bronchus ending in a blind pouch, absent pulmonary vasculature
- Chest radiograph: Agenesis/aplasia: Opaque hemithorax with ipsilateral mediastinal shift, hyperinflation of the contralateral lung
- CT: Differentiates by showing blind-ending bronchus in aplasia
- D/D: Collapse.
- Rudimentary bronchus and lung, with a decrease in the number and size of alveoli, airways and vessels
- Chest radiograph: Unilateral, small, hyperlucent lung with ipsilateral mediastinal shift
- CT: Asymmetric decreased lung parenchyma, narrow airways, decreased vascularityFigs 4.2A to C: Pulmonary aplasia in a neonate. CT scout film (A) showing small opaque right hemithorax with ipsilateral mediastinal shift. CECT chest axial soft tissue (B) and lung window (C) images show absent right lung parenchyma and right pulmonary artery, but presence of a rudimentary right bronchus (arrow).Figs 4.3A to E: Pulmonary hypoplasia. Chest radiograph reveals a small hyperlucent left hemithorax (A). CECT chest mediastinal and lung window images (B to E) show small left pulmonary artery (arrow), small volume left lung. Areas of mosaic attenuation are noted in both lungs.Figs 4.4A to D: Right upper lobe (RUL) agenesis. Chest radiograph shows a small opaque right hemithorax with ipsilateral mediastinal shift (A). CECT chest mediastinal and lung window images (B to D) reveal a small volume right lung, small right pulmonary artery (arrow) and absent right upper lobe bronchus.
- No air trapping on expiratory scans
- D/D: Swyer-James-McLeod syndrome (Figs 4.5A to D)
- Acquired abnormality, obliterative bronchiolitis secondary to childhood infections
- Unilateral, small, hyperlucent lung, air trapping on expiratory scan.
Scimitar Syndrome: Hypogenetic Lung Syndrome
Right pulmonary hypoplasia with anomalous vein draining into systemic veins and dextroposition of heart. Systemic arterial supply of affected lung lower lobe and associated cardiac anomalies might be present (Figs 4.6A to E).
Figs 4.5A to D: Swyer-James syndrome. CT scout film of a 8-year-old girl shows a small volume hyperlucent left hemithorax (A). CECT chest axial soft tissue (B) and lung (C) window images and coronal MinIP image (D) reveal a hyperlucent small volume left lung with areas of bronchiectasis and airtrapping on expiratory scan (not shown in image) and a small left pulmonary artery (arrow in B).
Chest radiograph: Pulmonary hypoplasia, curvilinear tubular opacity (scimitar-sword) along the right heart border (anomalous vein draining into IVC).
CT: Confirms diagnosis.
Treatment: Conservative.
Pulmonary Artery Anomalies
Pulmonary Artery Interruption (Figs 4.7A to F)
Proximal part of the pulmonary artery is attenuated, and systemic arterial supply to the affected lung via intercostal arteries.
Chest radiograph and CT: Small hemithorax, attenuated ipsilateral hilum absent or small ipsilateral pulmonary artery and subpleural reticular lines due to systemic collaterals.40
Figs 4.6A to E: Scimitar syndrome. CT scout film (A) of a 16-month-old girl child shows a curvilinear opacity in right lower lung zone (arrow). CECT chest (B and C) and CT angiography images (D and E) show abnormal curvilinear venous channel draining in the inferior vena cava (arrow).
Isolated Systemic Arterial Supply to Normal Lung
A segment of lung having normal communication with the tracheobronchial tree shows absence of normal pulmonary artery supply and abnormal systemic arterial supply. This is also termed as pseudosequestration.41
Figs 4.7A to F: Proximal pulmonary artery interruption. CT scout film (A) shows an opaque left hemithorax with ipsilateral mediastinal shift. CECT chest axial mediastinal and soft tissue window images (B to E) reveal right sided aortic arch (arrow in B), a normal right pulmonary artery and an attenuated left pulmonary artery just after the origin. The left lung is hypoplastic, multiple collateral vessels are seen as septal thickening in the peripheral subpleural location (arrow in E).
Pulmonary Venous Anomalies
Isolated pulmonary venous anomalies include partial and total anomalous pulmonary venous drainage, meandering pulmonary vein, scimitar variant, etc.42
Partial Anomalous Pulmonary Venous Drainage (PAPVC) (Figs 4.8A to C)
Superior or inferior pulmonary veins do not drain into the left atrium. When right sided, the veins drain into the superior vena cava or the right atrium. When left sided, they drain into the left brachiocephalic vein.
Total Anomalous Pulmonary Venous Drainage (TAPVC)
All the four pulmonary veins do not drain into the left atrium.
In supracardiac variety, they drain into the brachiocephalic vein. In cardiac type, they drain into the right atrium or coronary sinus. In infracardiac type, the venous drainage is into infradiaphragmatic veins.
Figs 4.8A to C: Partial anomalous pulmoanry venous drainage in a 14-year-old male. CECT chest axial image (A) shows a vascular structure coursing in the prevascular location (arrow). Coronal reformatted image (B) and coronal MIP image (C) shows the anomalous venous drainage of the left superior pulmonary veins into a venous structure (arrow) draining into the left brachiocephalic vein (long arrow).
Meandering Pulmonary Vein
A pulmonary vein has an anomalous course in the lung parenchyma before draining into left atrium. Also known as pseudo-scimitar syndrome, as the anomalous vein mimics a scimitar vein.
Unilateral Pulmonary Venous Atresia (Figs 4.9A to F)
Atretic pulmonary veins of one lung; ipsilateral, small, opaque hemithorax. Contralateral lung hyperlucent. Septal thickening on X-ray and CT due to collaterals.
Sequestration
Abnormal lung parenchyma that does not communicate with the tracheobronchial tree, anomalous systemic arterial supply (Figs 4.10 to 4.12).
Extralobar: Abnormal lung parenchyma with separate pleural covering and systemic arterial supply, drainage to systemic veins. Described as mixed bronchoarteriovenous malinosculation according to the new classification (Lee).
Intralobar: Abnormal lung parenchyma contained within visceral pleura, systemic arterial supply and venous drainage to pulmonary veins.
Commonest location: Left lower lobe.
Presentation: Recurrent infections (intralobar sequestration), incidental detection (extralobar sequestration).
Chest radiograph : Persistent mass/opacity. Lung bases commonest location. Contains air if secondarily infected.
CT/MRI: Anomalous systemic artery and venous drainage (extralobar).
Treatment : Resection if symptomatic.
Hamartomatous lesion of the bronchial tree with cystic and adenomatoid components. Termed as ‘congenital pulmonary airway malformations (CPAM)’. They develop as a result of abnormal bronchial branching.44
Figs 4.9A to F: Pulmonary vein atresia in a child with recurrent hemoptysis. CT scout film (A) shows a small volume left hemithorax. CECT chest and CT angiography (B to D) films show normal right pulmonary artery and pulmonary veins; nonvisualized left sided inferior pulmonary veins and a small artery. The lung window images (E and F) show septal thickening (arrow in E) predominantly at the left lung bases (due to collateral circulation).
Figs 4.10A to D: Intralobar pulmonary sequestration in an infant presenting with hemoptysis and melena. The CT scout film (A) shows an area of consolidation involving right lower zone paracardiac location. CECT (B) and CT angiographic images (C and D) reveal an area of consolidation in the right lower lobe, enlarged tortuous systemic arterial supply (arrow) to the sequestrated lung, and venous drainage in the right inferior pulmonary veins.
Presentation: Depends on the size of CPAM. Large lesions can cause respiratory distress in newborns. May be asymptomatic at birth. Recurrent infections and hemoptysis in older children.
Chest radiograph/CT:
- Imaging appearance depends on size and number of cysts:
- Type I—single or multiloculated large cysts
- Type II—multiple small cysts of 5–20 mm size
Figs 4.11A to E: Intralobar sequestration. CT scout film (A) reveal retrocardiac linear opacities (arrow). Chest CECT axial soft tissue and lung window images (B and C) show emphysematous left lower lobe and few enlarged tortuous vessels (arrow). CT angiographic MIP (D) and VRT (E) images reveal the systemic arterial supply from the abdominal aorta (block arrow). - Solitary, no lobar predilection
Figs 4.12A to D: Pulmonary sequestration mimicking hydatid cyst. Chest radiograph (A) of a 4-year-old male child shows a large mass in left lower zone, an imaging possibility of hydatid cyst was kept. Chest radiograph 3 months later (B) showed resolution of the lesion and a repeat radiograph 1 year later showed multiple ring shadows and consolidation in left lower zone and retrocardiac location (C). CECT chest axial soft tissue image (D) shows left lower lobe consolidation, areas of air and fluid filled cavities, and a large artery (arrow) arising from the descending aorta, supplying the affected lung.
D/D: Congenital diaphragmatic hernia.
Treatment: Resection.
Developmental abnormality due to abnormal budding from the foregut, leading to cyst formation. Commonest mediastinal cyst.
Figs 4.13A to D: Type I CCAM. Chest radiograph (A), CECT chest axial soft tissue (B) and lung (C) window images, and coronal reformatted lung window image (D) show a large air filled cyst involving the right upper lobe.
Chest radiograph: Well-defined, smooth Mediastinal or spherical mass.
CT: Cyst in mediastinal location (subcarinal and right paratracheal), less common-lung, close to bronchus. No internal air unless infected. Cyst wall enhancement and calcification might be seen.
D/D: Duplication cyst, neuroenteric cyst.
Treatment: Resection.
Congenital abnormality where one lobe of lung (less commonly, more than one lobe or one lung segment) is hyperinflated. Intrinsic or extrinsic abnormalities like bronchomalacia or mucosal web or vascular compression may result in airway compression and lobar hyperinflation.49
Figs 4.14A to C: Type II CCAM with infection. Chest radiograph (A) reveals a multiloculated air filled cystic lesion (arrow) in right paracardiac location. Chest radiograph 2 months later (B) shows obscured right CP angle and consolidation in right lower zone. CECT chest axial lung window image (C) reveals the CCAM as a multiloculated air filled cyst in right middle lobe (arrow), with thick wall and pleural effusion.
Figs 4.15A and B: Antenatal diagnosis of CCAM. Antenatal heavily T2W MR image (A) of the fetus in axial section reveals a multiloculated hyperintense lesion in right lung (arrow). CT of the thorax (B) in early neonatal period confirms the diagnosis of CCAM.
Presentation: Commonly present as respiratory distress in the neonate.
Chest radiograph : Initially, in a neonate, may appear as a soft-tissue density (due to retained fetal lung fluid).
Later: Unilateral hyperlucent lung with contralateral mediastinal shift or compression collapse of ipsilateral lung.50
Figs 4.16A and B: Bronchogenic cyst in a 3-day-old neonate. Chest radiograph shows a thin walled air filled cyst in left lung lower zone. (A) CT chest lung window axial image (B) shows the cyst to be located in left lower lobe, and having air fluid level within.
Figs 4.17A and B: Large intrapulmonary bronchogenic cyst in a 3-year-old male child presenting with dyspnea. Chest radiograph (A) and CT chest axial soft tissue window image (B) reveal a large fluid filled cyst in left lung upper lobe.
Figs 4.18A and B: Congenital lobar emphysema of left upper lobe. Chest radiograph (A) shows hyperlucent left hemithorax with contralateral mediastinal shift, herniation of left lung to the right side, and crowding of vessels in left lower zone. CT chest axial lung window image (B) shows hyperlucent emphysematous left upper lobe, which shows attenuated vascular markings.
Figs 4.19A to E: CLE and CCAM. Chest radiograph (A) shows hyperlucent left hemith orax with contralateral mediastinal shift and a thin walled cyst in left upper lung zone. CT chest lung window axial and reformatted coronal images (B to E) show the emphysematous left upper lobe and a thin walled air filled cyst in the left upper lobe.
CT: Hyperinflated lobe with attenuated vessels and mass effect. Left upper lobe most commonly affected.
Treatment: Resection of affected lobe.
Reference
- Lee ML, Lue HC, Chiu IS, Chiu HY, Tsao LY, Cheng CY, et al. A systematic classification of the congenital bronchopulmonary vascular malformations: Dysmorphogeneses of the primitive foregut system and the primitive aortic arch system. Yonsei Med J. 2008;49:90–102.
Etiology of pulmonary infections in children
- Bacterial infection
- Viral infection
- Fungal infection
- Parasitic infection.
Bacterial pneumonia
Patterns of bacterial pneumonia
Air Space Pneumonia or Lobar Pneumonia
- Result of Streptococcus pneumoniae and Klebsiella pneumoniae.Figs 5.1A and B: Bacterial pneumonia. CECT chest axial soft tissue (A) and lung (B) window showing consolidation and air bronchogram.
- Chest radiograph—usually unilateral disease, consolidation with air bronchograms with little or no volume loss
- Complications—more frequent than in viral pneumonias.
Streptococcus pneumoniae
- Most common cause of bacterial pneumonia in childhood
- Chest radiograph—consolidation usually confined to one lobe. Pleural effusions and empyema are uncommon.
Klebsiella pneumoniae (Figs 5.3A to D)
- Uncommon except in the presence of chronic lung disease
- Chest radiograph—lobar consolidation with air bronchogram, increase in lung volume causing expansile pneumonia
- Complications—empyema and abscess.
Bronchopneumonia
- Insult occurs at the terminal and respiratory bronchioles spreading to peribronchiolar alveoli
- Chest radiograph—patchy lobular consolidation with volume loss. Bilateral involvement is common and accompanying pleural effusions may be seen.
Staphylococcus aureus
- Mainly infects infants under 1 year of age
- Chest radiograph—lobular or bronchopneumonic pattern. Frequently pleural effusions and empyema. Embolic form of disease may result in nodular masses or abscesses
Haemophilus pneumoniae
- Gram-negative bacteria. Can cause bronchiolitis, pneumonia, epiglottitis and meningitis
- Incidence sharply reduced since the onset of immunization
Figs 5.4A and B: Staphylococcal pneumonia in a child. CECT chest axial lung window images reveal multiple nodules in both lungs lower lobe, some thin walled air filled cysts (pneumatocele) shown with arrows. Note associated right pleural effusion.
Figs 5.5A and B: Staphylococcal pneumonia with pneumatocele and right sided empyema. CECT chest axial soft tissue window images show right lower lobe pneumatoceles (arrow) and right empyema.
Mycoplasma pneumoniae
- Seen in school aged children. Radiological changes are more severe than clinical symptoms
- Radiograph—interstitial opacities and/or patchy air space opacification, pleural effusions, hilar lymph nodes. Complications are rare.
Round Pneumonia
- Seen in children less than 8 years of age due to paucity of collateral channels of ventilation
- Most often a result of Streptococcus pneumoniae and may simulate a mass lesion
- Chest radiograph—round mass like lesion, often involving the lower lobes. Ill defined borders in at least a part of the border and may contain air bronchogram (Fig. 5.6).56
- Diagnosis should always be considered in a child with fever with a rounded mass like lesion on chest radiograph
- Follow up radiograph—recommended to ensure complete clearance in order to rule out an underlying mass
- Differential diagnosis:
- Bronchogenic cyst
- Neuroblastoma
- Pulmonary sequestration.
Viral pneumonia
- Most common cause of respiratory infection in children
- Most common causes of viral pneumonia are RSV, parainfluenza, influenza A and B and adeno viruses
- Chest radiograph—hyperinflation, areas of atelectasis, bilateral perihilar symmetric infiltrates. Lack of focal lung consolidation (which is the hallmark for bacterial pneumonia) (Figs 5.7A to C)
- Children are more predisposed to hyperinflation and atelectasis in contrast to adults, as they have smaller airways with more abundant mucus production and poor collateral pathways of ventilation.
Swyer-James-McLeod Syndrome (Also see Chapter 4)
- A form of post-infectious obliterative broncholitis that follows an insult to the developing lung (before the age of 8 years)
- Chest radiograph:
- Predominantly unilateral transradiancy (reflecting hypoplasia of pulmonary vasculature and obliterative bronchiolitis)
- Small lung and small hilum
- Ipsilateral air trapping—key finding.
- CT:
- More commonly shows areas of bilateral abnormalities depicting areas of decreased attenuation.
- Expiratory scans can confirm air trapping.
- Cylindrical bronchiectasis, collapse and scarring may be seen.
- Differential diagnosis—unilateral translucent lung may result from technical causes (rotation), chest wall defect (Poland syndrome—absent pectoralis major), pleural causes (pneumothorax/contralateral pleural effusion), pulmonary causes (bronchial obstruction by a foreign body, pulmonary emphysema) and vascular causes (pulmonary artery hypoplasia, pulmoniary thromboembolism)
Indications of CT in Pneumonia
- For complications of bacterial pneumonia:
- Pleural complications
- Lung parenchymal complications
- Pericardial complications
- Aim is to differentiate suppurative pleural from parenchymal pathology. Former requires interventional procedures while lung parenchymal complications are managed conservatively
- To exclude underlying abnormality in recurrent infection/non-resolving pneumonia
- Investigation of immunocompromised children with normal radiograph but with clinical suspicion of respiratory infection
- To guide the type and site of tissue sampling.
Complications of Pneumonia
Pleural Complications
Pleural effusion and empyema
- Most commonly due to S. pneumoniae, S. aureus, H. influenzae, Mycoplasma pneumoniae, Pseudomonas spp.
- Parapneumonic effusion (PPE)—pleural fluid collection adjacent to infected lung (Figs 5.2B and C).
- May be simple or complicated depending on whether the infective organism is present or not within the collection.
- Empyema (Fig. 5.5A) —when there is frank pus within the collection
- An anechoic collection may contain frank pus.
- Decision to drain is dependent not on the imaging findings but on the clinical status:
- Increasing size of collection
- Respiratory embarrassment due to the collection.
- Differential diagnosis of lung abscess:
- Irregular thick wall and acute angle with chest wall—lung abscess
- Split pleura sign and compression of the adjacent lung—empyema.
Lung Parenchymal Complications
- Cavitary necrosis
- Pulmonary abscess
- Pulmonary gangrene
- Pneumatocele
- Bronchopleural fistula.
The names given to the suppurative process depends on several factors including the severity, distribution, and condition of the adjacent 59lung parenchyma and temporal relationship with development of pneumonia.
Cavitary Necrosis (Figs 5.8A to C)
- S. pneumoniae and S. aureus are the frequent associated organisms.
- Defined as a dominant area of necrosis with associated variable number of thin walled cysts.
- CT—decreased contrast enhancement, lack of normal lung architecture, loss of lung pleura margin, multiple thin walled cavities filled with air or fluid with no peripheral enhancement.
- Differential diagnosis—underlying cystic adenomatoid malformation, lung abscess.
Lung Abscess (Fig. 5.9)
- Defined as collection of fluid or air within the lung parenchyma with a well defined enhancing rim.
Figs 5.8A to C: Cavitary necrosis in bacterial pneumonia. Chest radiograph (A), CECT chest axial soft tissue (B) and lung (C) window reveal extensive consolidation involving both lower lobes, with areas of breakdown.
Pneumatoceles (Figs 5.10A and B)
- Thin walled cysts on imaging and may represent a later or less severe stage of resolving or healing necrosis. They may have air fluid levels.
- Although pneumatoceles are most characteristic of staphylococcal pneumonia, other causes are Pneumococcus, H. influenzae, Streptococcus, M. tuberculosis and E. coli. They are also known after hydrocarbon ingestion.
Bronchopleural Fistula
- Communication between a bronchus and the pleural cavity.
- Most commonly follows pneumonectomy, may follow lung abscess, bacterial or fungal pneumonias and tuberculosis.
- CT—may show direct communication between the pleural space and the bronchial tree (Fig. 5.11).
Pericardial Complications
Purulent pericarditis (Fig. 5.2C).
Fig. 5.9: Lung abscess. CECT chest axial soft tissue window image reveals low density area showing air focus, within a consolidated right upper lobe.
Figs 5.11A and B: Bronchopleural fistula. CT chest shows large right hydropneumothorax with chest tube in situ (in B). The communication between the bronchus and pleural cavity is well seen (arrow in A).
Recurrent/Nonresolving Pneumonia
- Aspiration syndromes—swallowing disorders due to neuromuscular disorders or immaturity, gastroesophageal reflux (Figs 5.12A and B), H. type fistula, esophageal obstruction (foreign body, vascular ring) Underlying developmental lesions—like congenital cystic adenomatoid malformation, bronchogenic cyst, sequestration (described in the respective chapter)
- Bronchial obstruction—foreign body, neoplasm, stricture (Figs 5.13A to D)
- Underlying systemic disorders—immunodeficiency (congenital and acquired), asthma, cystic fibrosis (Figs 5.14A to E) (also see chapter 12), immotile cilia syndrome.
Tuberculosis
Primary tuberculosis is the most common form of tuberculosis in childhood, radiologically distinct from post-primary tuberculosis, the most common form occurring in adults (also see chapter 6).
Fungal infections
Mostly seen in immunocompromised patients. May occur in immunocompetent patients. Necrosis, cavitation, calcifications, chronic inflammatory reaction, pleural disease may all occur.
Two organisms most common
Figs 5.12A and B: Recurrent pneumonia in a child with Down's syndrome with gastroesophageal reflux. CT thorax axial lung window sections reveal consolidation in bilateral lung dependent locations.
Figs 5.13A to D: Non-resolving pneumonia in a 5-month male child due to segmental bronchial narrowing. Chest radiograph (A) revealed right mid zone consolidation. CT chest axial (B to D) images show the right upper lobe anterior segment consolidation and hyperlucency suggesting obstructive hyperinflation. Coronal reformatted image revealed narrowing of right upper lobe segmental bronchial narrowing.
Figs 5.14A to E: Non-resolving pneumonia in a 7-year male with cystic fibrosis. Chest radiograph (A) shows bilateral hyperinflated lung fields, cystic bronchiectasis, elongated soft tissue shadows (bronchocele) in right lower lung zone, and consolidation in left middle lung zone. CECT chest axial soft tissue (B) and lung window (C to E) images reveal left lung upper lobe consolidation, bilateral central bronchiectasis, bronchocele (arrow).
Actinomyces
- Actinomyces israellii, an anaerobic organism has both bacterial and fungal properties.
- Aggressive invasion of the thoracic wall when present is characteristic. Distinguishes this from fungal infections other than mucormycosis.
Aspergillosis
Aspergillus can produce four distinct patterns in children depending on immune status and patient's pre-existing disease.
Fungal Balls or Mycetoma
- Form in pre-existing cavities formed by tuberculous infection, bronchiectasis or fibrotic lung disease.
- Are unusual in children.
- Mobile except when it nearly completely fills the cavity with no space to move around.
- Differential diagnosis—air crescent sign of invasive aspergillosis. does not have a background of fibrocavitatory disease.
Allergic Bronchopulmonary Aspergillosis (Figs 5.15A to E)
- Hypersensitivity reaction to the presence of Aspergillus fumigatus.
- Most commonly seen in association with asthma and cystic fibrosis.
- Radiographs and CT:
- Gloved finger appearance due to mucin filled bronchi outlined because of collateral air drift.
- Patchy areas of atelectasis and emphysema.
- Central bronchiectasis.
Invasive Aspergillosis
- In immunocompromised neutropenic patients with leukemia or after bone marrow or solid organ transplantation.
- May be airway invasive or angioinvasive. The two forms may coexist and it is not always possible to distinguish between the two types.
- Airway invasive form:
- Angioinvasive form (Figs 5.16A and B):
- Wedge shaped opacities resulting from infarction.
- The ‘halo sign’—represents hemorrhage surrounding the nodule due to vascular invasion.
- The ‘air crescent sign’—seen in the recovery phase when neutrophillic count rises; retraction of the necrotic lung from the viable lung parenchyma resulting in a crescent of air collection partially outlining the necrotic lung.
Figs 5.15A to E: ABPA in a 10-year male child with history of asthma. Chest radiograph (A) reveals bilateral hyperinflated lung fields, tubular elongated soft tissue opacities in perihilar location of bronchoceles. CECT chest (B to E) shows central bronchiectasis and mucus filled dilated bronchi (bronchoceles).
Semi-invasive Aspergillosis (Figs 5.17A to C)
- Less aggressive form seen in patients with underlying lung disease or with mild immunosuppression.
- Also known as chronic airway invasive aspergillosis.Figs 5.16A and B: Angioinvasive aspergillosis. CT thorax axial lung window images reveal multiple nodules and consolidation, with surrounding ground glass halo.67Figs 5.17A to C: Semi-invasive aspergillosis. CT thorax reveals left upper lobe consolidation with cavitation. Another nodule is visualized in right upper lobe.
- May mimic reactivation tuberculosis.
- Starts as a focus of consolidation and cavitation in the upper lobes with pleural thickening.
Parasitic infections
Hydatid disease of the lung (Figs 5.18A to C)
- Larval stage of Echinococcus granulosus, is the most frequent cause.
- In children, commonest site—lungs, in adults the commonest site—liver
- On imaging:
- Intact cysts are seen as sharply defined round to oval masses of variable size.
- Lung cysts rarely calcify.
- Rupture or superimposed infection may result in varied appearances giving rise to air crescent sign, air bubble sign, water lily sign, mass within cavity sign and ring enhancement sign.
Sites of involvement
- Parenchymal
- Lymph nodal
- Pleural
- Airway.
Parenchymal
- Pulmonary primary complex (PPC)—commonest
- Progressive primary disease (PPD)
- Postprimary lesion (PPL)/Reactivation.
Consolidation—unifocal, homogeneous, ill-defined margins, any lobe, right side commoner. Same side as nodal enlargement in 2/3rd—primary pulmonary complex.
Progressive Primary Disease (PPD)
Result of progression or reactivation of the primary disease.
Consolidation—heterogeneous, poorly marginated, often more than one pulmonary segment is involved, may cavitate or maybe associated with collapse. Lobar or complete lung involvement possible (Figs 6.3 to 6.6).
- Bronchopneumonia (spread through tracheobronchial tree)
Fig. 6.1: Primary pulmonary complex. Chest radiograph showing consolidation of the right upper lung zone in a 11-year-old male child.
Figs 6.2A to C: Primary pulmonary complex. CT scout film showing right pleural effusion, and axial contrast-enhanced computed tomography (CECT) scan mediastinal window (B) and lung window (C) show medistinal and right hilar lymphadenopathy lung window image shows small of subpleural area of consolidation.
Figs 6.3A to D: Progressive primary disease. CECT chest lung window (A to C) and mediastinal window (D) show multifocal consolidation involving left lung lingular and lower lobe, with centriacinar nodules showing tree in bud pattern (endobronchial spread).
Figs 6.4A to C: Progressive primary disease. CT scout film shows extensive left lower zone and right paracardiac consolidation (A). CECT chest mediastinal (B) and lung window (C) images show multifocal consolidation involving left lung upper and lingular lobe, right middle lobe, with centriacinar nodules showing tree in bud pattern (endobronchial spread).
Figs 6.5A to C: Progressive primary disease in the lung with hematogenous dissemination of tuberculosis in a 6-month-old male child. CECT chest (A and B) reveals extensive mediastinal adenopathy and centriacinar nodules scattered in both the lungs. CECT brain (C) show multiple ring-enhancing lesions in the left basal ganglia and left cerebellar hemisphere.
Figs 6.6A to C: Progressive primary disease in a 15-year-old girl. Chest radiograph reveals widening of the right paratracheal stripe (arrow in A). CECT chest axial soft tissue (B) and lung (C) window reveal necrotic right paratracheal adenopathy and extensive centrilobular nodules in bilteral lungs (bronchopneumonic pattern).
Figs 6.7A and B: Miliary TB. Chest radiograph (A) and chest CT (B) reveal uniform miliary nodules scattered in both the lungs.
Figs 6.8A and B: Postprimary disease with reactivation and endobronchial spread. Chest radiograph (A) shows bilateral upper lobe consolidation. CECT chest axial lung window image (B) shows bilateral upper lobe consolidation and adjacent centriacinar nodules suggesting endobronchial spread.
Postprimary Disease
- Unusual in children, when seen is usually in adolescents
- Characterized by parenchymal disease with an anatomic bias for the upper lung zones, typically in the apical and posterior segments of the upper lobes and superior segments of the lower lobes
- Radiograph: Cavitation is characteristic
Lymphadenopathy
Hallmark: Parenchymal and nodal involvement or isolated nodal involvement. Right paratracheal, hilar and subcarinal—most common sites (Figs 6.10 and 6.11).
CT: Nodes show central necrosis (Figs 6.12 and 6.13), ghost-like or heterogeneous (Fig. 6.14) or even homogeneous (Fig. 6.15) enhancement.73
Figs 6.9A to C: Postprimary disease with reactivation. Chest radiograph (A) CECT chest axial mediastinal (B) and lung window (C) reveal-thick walled cavity in left upper lobe, with adjacent consolidation and right paratracheal adenopathy.
Figs 6.10A to C: Right paratracheal and right hilar lymphadenopathy in tuberculosis. Chest radiograph (A) and CECT (B and C) shows the necrotic lymph nodes (arrow).
Figs 6.12A and B: Enlarged necrotic conglomerate right paratracheal, prevascular and left axillary lymph nodes.
Figs 6.13A and B: T1W (A) and T1W fat saturated postcontrast (B) axial MRI images reveal necrotic left hilar adenopathy in an adolescent girl.
Figs 6.15A to C: Chest radiograph (A) and CECT chest (B and C) showing enlarged right paratracheal, subcarinal and right hilar lymph nodes.
Obscuration of perinodal fat and conglomeration signs of activity. Calcification (Fig. 6.16) maybe seen initially, increases with treatment.
Pleural effusion is more common in adults and teenagers than in children.
- Unilateral, free flowing initially
- With or without lung lesion.
Complications: Empyema, bronchopleural fistula, pyopneumothorax, fibrothorax.
Fig. 6.17: CECT chest showing mild right pleural effusion and right lung consolidation in a case of primary disease.
Fig. 6.19: Complication of pleural effusion. CECT chest showing left pleural collection with pleural enhancement and ‘split pleura’ sign suggestive of empyema (arrow).
Figs 6.20A and B: Compression of bronchus intermedius by an enlarged necrotic right hilar lymph node leading to atelectasis of right middle and lower lobes. CECT thorax coronal reformatted images reveal the node (arrow) and the obstruction at bronchus intermedius (block arrow).
Airway
Atelectasis caused by compression by enlarged nodes (Figs 6.20A and B).
Common sites: anterior segment of upper lobe or medial segment of middle lobe (Figs 6.21A and B). Enlarged necrotic nodes may erode into bronchus.
Chest Wall
- Osteomyelitis of chest wall bones
- Sternum, ribs, vertebrae
- Bone destruction with abscess/collection showing peripheral enhancement (Figs 6.22A and B).
Figs 6.21A and B: Right middle lobe collapse. CECT thorax coronal reformatted lung window image (A) and axial soft tissue window image (B) show the collapsed RML as a triangular opacity (arrow).
Figs 6.22A and B: CECT chest axial (A) and sagittal reformatted bone window (B) images reveal destruction of sternum (arrow) and the fifth thoracic vertebral body, with paraspinal soft tissue and localized angular kyphosis.
Signs of Activity
Parenchyma
- Active: Thick-walled cavities, consolidation and centrilobular nodules.
- Inactive: Thin-walled cavities, fibrotic bands and well-defined nodules.
Nodes
- Active: Node enhancement (rim or inhomogeneous), conglomeration and obscuration of perinodal fat. Active nodes can also be occasionally homogeneous.
Sequelae
- Calcification of nodes or parenchymal lesions in about one-thirds.
- Bronchiectasis and fibrocavitary changes in PPD (Fig. 6.23).
Classification
Development and branching anomalies |
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Extrinsic airway compression |
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Intrinsic airway abnormalities |
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Intraluminal airway obstruction |
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Small airway abnormalities |
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Development and Branching Anomalies of Upper Airways
Congenital Anomalies of Development of Tracheal Bud
- Tracheal atresia, agenesis, stenosis, tracheal web and broncho-pulmonary foregut duplication cyst are rare congenital anomalies of development of tracheal bud, presenting as neonatal respiratory distress
- Tracheal atresia and agenesis are rare congenital anomalies presenting with respiratory distress immediately after birth. Three types (type I-III) of tracheal agenesis are described depending on the severity
- Congenital tracheal web and stenosis result from failure of complete resorption of epithelium and incomplete recanalization during the development of tracheal bud
- Tracheal web presents with a membrane encircling the tracheal lumen causing luminal narrowing
- Congenital tracheal and subglottic stenosis are the commonest upper airway anomaly requiring tracheostomy in children.
- Congenital subglottic stenosis can be membranous or cartilaginous
- Congenital tracheal stenosis can be either generalized (hypoplasia) or segmental stenosis
- Bronchopulmonary foregut duplication cysts can be classified either as bronchogenic or esophageal cyst
- Bronchogenic cysts are commonly located in right paratracheal or subcarinal location. When large, they may cause airway compression.
Cleft Palate
- Can be associated with cleft lip or present as an isolated anomaly
- Cleft palate can be of variable severity—bifid uvula, cleft involving soft palate only, cleft involving both soft and hard palate (Figs 7.1A and B).
- Cleft palate can present with choking while feeding
Figs 7.1A and B: Cleft palate. Axial CECT image (A) soft tissue window and coronal minimum intensity projection (MinIP) (B) reveals a complete cleft involving the soft as well as hard palate (arrow).
Disorders of Tracheoesophageal Septum Development and Fusion
- Primordial respiratory tract arises from a diverticulum of the foregut
- Tracheooesophageal septum develops between the two and separates the developing upper airway and the pharynx/cervical esophagus
- Laryngeal cleft and tracheo-esophageal fistulae are rare disorders of fusion of trachea-esophageal septum and cricoid cartilage
- Laryngeal cleft is a rare congenital anomaly of abnormal communication between the larynx/trachea and the foregut (Figs 7.2A to D)
- Usual clinical presentation is with choking/aspiration while feeding, stridor, recurrent pneumonia, chronic cough and cyanosis
- Four types are described by Bejnamin and Inglis, depending on the level of communication83Figs 7.2A to D: Type I laryngeal cleft. Frontal chest radiograph (A) of a neonate shows the location of the nasogastric and the endotracheal tube overlapping in the same location in supraglottic location. Sequential axial CECT neck images (B to D) separate airway and pharynx in B (arrows); whereas in subsequent caudal sections the larynx and pharynx are seen to communicate in a single tube (arrow in B and C).
- Tracheoesophageal fistula is usually associated with esophageal atresia and presents with neonatal respiratory distress, choking and cyanosis while feeding.
- H-type tracheo-esophageal fistula (Figs 7.3A to C) presents in older children with recurrent respiratory infection
Disorders of Tracheal and Bronchial Branching
- Disorders of tracheal and bronchial branching include tracheal bronchus, tracheal diverticulum, tracheal trifurcation etc.
- Tacheal bronchus (pig bronchus) is an anomalous origin of bronchus above the carina, usually on the right side (Fig. 7.4)
- Usually incidentally detected, tracheal bronchus can rarely present with recurrent infections of the involved lobe (Figs 7.5A to C)
- Tracheal trifurcation is an anomalous division of trachea into three segments in stead of two segmentsFigs 7.3A to C: H-type tracheo-esophageal fistula with recurrent respiratory infection. Axial CT of thorax lung window (A) and coronal reformatted MinIP image (C) showing the fistulous tract (arrows). Axial CT thorax lung window (B) showing multifocal consolidations in bilateral lungs.Fig. 7.4: Tracheal bronchus in an asymptomatic child. Coronal MinIP image shows the origin of right upper lobe bronchus (arrow) from the trachea above the carina.85Figs 7.5A to C: Tracheal bronchus with right upper lobe infection. CT scout image shows the origin of right upper lobe bronchus above carina (A). axial CT of chest lung window (B) and coronal reformatted image (C) shows evidence of consolidation in the upper lobe.
- Tracheal diverticulum is due to abnormal supernumerary branching of trachea. The diverticulum usually is related to the right posterolateral wall of trachea and communicates with tracheal lumen.
Disorders of Bronchial Bud Development
- Pulmonary agenesis results from development of bronchial bud leading to non-development of pulmonary parenchyma (Figs 7.6A to D).
- A blind ending bronchial bud and absent pulmonary parenchyma are the usual findings in pulmonary aplasia
- Pulmonary artery can be absent in both pulmonary agenesis and aplasia.
- Pulmonary hypoplasia (Figs 7.7A to C) can result from absence of segmental bronchus and vessels.
- Congenital bronchoesophageal fistula (Figs 7.8A to E) are rare disorders of abnormal communications of the esophagus with the bronchi.Figs 7.6A to D: Left sided pulmonary agenesis in a 7-year-old male. Chest radiograph PA view (A) reveals an opaque left hemithorax and herniation of right lung into left hemithorax. Axial CECT chest mediastinal window (B) and lung window (C); and coronal MinIP image (D) reveal prsence of normal right pulmonary artery and normal right main bronchus (arrows). Left pulmonary artery and left main bronchus are not visualized.Figs 7.7A to C: Right pulmonary hypoplasia. Frontal chest radiograph (A) reveals a small right hemithorax and elevated right hemidiaphragm. Axial contrast enhanced T1W fat saturated MR image (B) reveals a small right pulmonary artery (arrow) and normal sized left pulmonary aretry. Note the small right lung volume. Coronal MinIP CT image (C) reveals short right main bronchus (arrow), absence of right upper lobe bronchus, and bronchiectasis in the right lower lobe.They are divided into four types depending on the level of communication.
- Bronchial atresia (Fig. 7.9A to D) is due to segmental obliteration of the lumen of a bronchus leading to proximal mucoid impaction, and is usually asymptomatic.
- Imaging findings are tubular fluid-filled proximal bronchus and distal segmental hyperlucency and reduced vascularity.
Abnormality in Dimension of Large Airways
- Primary tracheobronchomalacia is abnormal collapsibility of tracheal and bronchial cartilages which lead to collapse of the larger airways on expiration (Figs 7.10A to D).87Figs 7.8A to E: Pulmonary hypoplasia (right upper lobe agenesis) with esophago-bronchial fistula in a neonate. Frontal chest radiograph (A) reveals opaque right hemithorax with ipsilateral mediastinal shift and compensatory hyperinflation of left lung. Axial CECT chest mediastinal window (B) reveals a normal size LPA (block arrow); whereas RPA could not be well visualized. Hypoplastic right lung parenchyma (lower lobe) shows consolidation (arrow). Coronal MinIP image (C) shows the small right main bronchus (arrow). Contrast esopahgogram oblique image shows opacification of the right lower lobe bronchus with barium, suggesting a bronchoesophageal fistula. Subsequent NCCT chest axial image (E) reveals barium within right lung lower lobe (block arrow).Figs 7.9A to D: Bronchial atresia in an adult. CT scout film (A) shows an elongated soft tissue opacity in left parahilar location (arrow). CECT chest (B and C) and coronal MinIP image (D) show a low attenuation lobulated density structure in left upper lobe centrally (arrow in B and C) and distal air trapping involving the left upper lobe.
- Primary tracheomalacia is commoner than bronchomalacia.
- Primary tracheomalacia is diagnosed on imaging when the expiratory collapse of the tracheal diameter is more than 50% of the inspiratory diameter.
- The diagnosis of tracheomalacia can be missed on a single phase inspiratory scan.
- ‘Expiratory frown sign’ in tracheomalacia refers to abnormal increased inward convexity of the posterior wall of trachea on expiration.
- Complete tracheal cartilage rings is a congenital anomaly where the posterior membranous wall of trachea is replaced by cartilage, causing a complete ring.
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Figs 7.10A to D: Primary tracheomalacia in a 3 month old male child. Inspiratory (A) and expiratory (B) axial CECT of neck reveal abnormal flattened configuration of the posterior wall of trachea (arrow) in expiratory scan. Coronal MinIP (C) and volume rendered image (D) show the narrowing of the tracheal lumen (arrows).
- Complete tracheal rings are often associated with other congenital upper airway and vascular anomalies.
- Axial CT scan shown the lumen of trachea to have a round shape instead of a semicircular configuration (Figs 7.11A and B).
Extrinsic Airway Compression
Extrinsic Vascular Compression
- Vascular rings causing airway compression include double aortic arch, right aortic arch with aberrant left SCA and ligamentum arteriosum
- Pulmonary artery sling is aberrant origin of the left pulmonary artery (LPA) from the right pulmonary artery (RPA), where the LPA takes a retrotracheal course and cause impression on posterior wall of trachea (Figs 7.12A and B)
Figs 7.11A and B: Complete tracheal cartilage rings associated with PDA in a neonate. Axial image of the thoracic CT angiography reveals the PDA (arrow). Caudal section shows a dilated pulmonary artery; narrowing and rounded contour of the trachea (arrow).
Figs 7.12A and B: Pulmonary artery sling and complete tracheal cartilage ring in a 4 month old child. Axial CECT of chest (A) reveals aberrant origin of the LPA (arrow) from the RPA; thus having a retrotracheal course. Note the rounded contour of trachea, suggesting presence of complete tracheal cartilage rings. Coronal MinIP image (B) shows the characteristic ‘T-shaped’ carina associated with the entity.
- Innominate artery compression syndrome results from abnormal origin of the innominate artery from the arch of aorta (far left origin); with a long course of the innominate artery in the superior mediastinum anterior to trachea and compression and indentation of anterior tracheal wall
- Enlarged thymus also implicated to have a role in tracheal compression in this syndrome
- The condition is often self-limiting
- Other causes of vascular compression on major airways include enlarged main pulmonary artery, RPA, LPA in pulmonary artery hypertension causing main bronchial compression (Figs 7.13A to D)
- Aberrant right subclavian artery usually does not cause tracheal compression as it has a retro-esophageal course (Figs 7.14A and B).
Extrinsic Compression-masses
- Enlarged mediastinal lymph nodes in tuberculosis or fungal infection can cause extrinsic compression on the trachea or main bronchi.Figs 7.13A to D: VSD with pulmonary hypertension and bilateral main bronchus compression. Frontal chest radiograph (A) shows cardiomegaly and enlarged proximal pulmonary arteries (arrow) with peripheral pruning; suggesting pulmonary artery hypertension. Axial CECT chest soft tissue window (B) reveals enlarged main pulmonary artery, RPA and LPA. The RPA and LPA lie anterior to the main bronchii. Axial CECT lung window (C and D) reveals narrow caliber of the main bronchii. Note the anterior impressions on the bronchii, caused by the pulmonary arteries.Figs 7.14A and B: Aberrant right subclavian artery (A and B). Axial CECT chest images show the origin of the right subclavian artery as the last branch of the aortic arch (block arrow) and its retroesophageal course (arrow).Figs 7.15A to C: Bronchial compression by metastatic mediastinal lymph nodes from neuroblastoma. Axial CECT chest mediastinal (A) and lung (B) window reveals the enlarged right paratracheal lymph nodes causing compression of trachea. Axial CECT image of the abdomen (C) shows the right suprarenal mass with calcification (arrow)
- Enlarged metastatic mediastinal lymph nodes can also cause extrinsic compression on the trachea or main bronchi (Figs 7.15A to C)
- Other causes of extrinsic compression on trachea and main bronchi include mediastinal cystic masses (Figs 7.16A to D) or unusual mesenchymal tumors (Figs 7.17A to D).
Figs 7.16A to D: Extrinsic compression of right main bronchus by neuroenteric cyst. Frontal chest radiograph (A) shows widened thoracic spinal canal (arrow). Lateral chest radiograph shows a posterior mediastinal mass (B). Axial CECT chest lung (C) and mediastinal (D) window show a cystic posterior mediastinal mass (block arrow) causing compression and displacement of the right main bronchus (short arrow).
Intrinsic (Intramural) Upper Airway Abnormality
Iatrogenic Strictures and Fistulae
- Prolonged endotracheal intubation may lead to tracheal stenosis, subglottic stenosis
- Stricture more likely with cuffed endotracheal tube with higher cuff pressure (>30 mm Hg) and prolonged intubation time leading to wall ischemia and fibrosis
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Figs 7.17A to D: Airway compression by an infiltrative enhancing mass which turned out to be hemangioma. Axial CECT of the neck and thorax (A to C) show an enhancing mass in the neck and superior mediastinum causing compression and narrowing of trachea and right main bronchus (arrows). Axial CT of thorax lung window reveals the narrowing of the right main bronchus (arrow in D).
- Imaging helpful in detecting extension of stricture (Fig. 7.18A to C)
- Treatment modalities include rigid bronchoscopy with balloon dilation, stenting or surgery
- Esophagopleural fistula is an uncommon iatrogenic complication of esophageal procedures (NG tube insertion, balloon dilation) or surgery (Figs 7.19A and B).
Inflammatory Upper Airway Lesions: Stricture
- Acute inflammatory involvement of the upper airway can be either tracheitis, or bronchitis
- Chronic inflammation can lead to tracheal or bronchial stricture
- Tuberculosis can involve either trachea or the main bronchi, leading to stricture (Figs 7.20A to C)95Figs 7.18A to C: Post-intubation tracheal stenosis. Axial CECT of neck (A), coronal (B) and sagittal (C) MinIP images show the extent of stenosis (arrow).Figs 7.19A and B: Postoperative esophagopleural fistula. Supine (A) and oblique (B) projection from an iodinated contrast study reveal accumulation of the esophageal contrast material into the left pleural cavity (arrow).
- Left main bronchus is the most common site of tubercular stricture (Figs 7.21 and 7.22) although other bronchi can also be involved (Figs 7.23A and B).
Bronchiectasis
- Bronchiectasis results from irreversible damage to the bronchi leading to dilated bronchi.
- Causes of bronchiectasis include recurrent respiratory infection, congenital immunodeficiency, inflammatory bronchial strictures, tuberculosis (Figs 7.24A to C), ciliary dysmotility, allergic bronchopulmonary aspergillosis or cystic fibrosis.
- ABPA and cystic fibrosis (Figs 7.25A and B) can result in central bronchiectasis of both the lungs; whereas focal bronchiectasis can be a result of bronchial stricture or extrinsic compression (Figs 7.26A to D).
Figs 7.21A to D: Tubercular LMB stricture. Axial CT chest at the level of carina (A) shows an irregular narrowing of the calibre of left main bronchus (arrow). Also note the centriacinar nodules in the left upper lobe, suggesting active infection. Coronal MinIP image (B) shows the left main bronchus narrowing and the left lower lobe collapse. Volume rendered image (C) shows absence of aeration of the left lower lobe. Virtual bronchoscopic image (D) shows the luminal narrowing of left main bronchus (arrow).
Figs 7.22A and B: Axial CECT of chest mediastinal (A) and lung window (B) showing LMB stenosis at the origin with left lung collapse.
Figs 7.23A and B: LUL stricture. Axial CT of chest lung window (A) and coronal MinIP image (B) show non-visualization of left upper lobe bronchus, and hyperinflated left upper lobe (arrows).
Figs 7.24A to C: Tubercular stricture of right main bronchus with bronchiectasts. Chest radiograph PA view (A) shows tubular bronchiectasis in right paracardiac location. Axial CECT chest mediastinal (B) window shows calcified mediastinal lymph node and right hilar necrotic lymph node. Axial CT lung (C) window shows strictur involving right main bronchus with distal bronchiectasis of right lower lobe segmental bronchi. Note the hyperlucent right lung field secondary to air trapping, associated with bronchial and bronchiolar inflammation.
Figs 7.25A and B: Cystic fibrosis in a young male. Chest radiograph PA view (A) shows bilateral central bronchiectasis. Axial CT chest lung window (B) shows widespread bronchiectasis in both the lungs, some showing mucoid impaction in right lower lobe. Note the air trapping in the lower lobes and right middle lobe (arrows).
Figs 7.26A to D: Peribronchial mass with bronchiectasis. Chest radiograph frontal view (A) shows complete opaque right hemithorax with ipsilateral mediastinal shift. Axial CECT chest mediastinal window (B) and lung window (C) and coronal MinIP image (D) show an infiltrative mediastinal mass causing complete occlusion of the right main bronchus and destruction and bronchiectasis of right lung.
Intraluminal obstruction
Foreign Body Inhalation
- Common cause of unilateral hyperlucent lung in children
- Right main bronchus is common area of impaction because of its more straight course
- Complete obstruction leads to collapse of the lobe subtended by the bronchus
- Partial obstruction leads to obstructive emphysema
- Metallic foreign bodies can be visualized on chest radiograph (Figs 7.27A to C)
- Organic foreign bodies (ex- peanut) are the most common to be inhaled and difficult to retrieve as they tend to swell and get fragmented (Figs 7.28A to C).
- Organic foreign bodies are not detected on chest radiograph; key finding is unilateral hyperlucent lung with air trappingFigs 7.27A to C: Metallic foreign body in right lower lobe bronchus. Chest radiograph PA view (A), axial CECT of chest mediastinal (B) and lung (C) window reveal the metallic foreign body in right lower lobe bronchus.Figs 7.28A to C: Organic foreign body (peanut) in right lower lobe bronchus leading to right lower lobe collapse. Chest radiograph PA view (A) shows right lower lobe collapse but no intrabronchial foreign body could be visualized. Coronal reformatted (B) and axial (C) image of CECT chest reveal fragmented intraluminal foreign body in the right lower lobe bronchus and lower lobe collapse.
- Long- standing foreign body may cause bronchial fibrosis and stricture (Figs 7.29A to C).
Masses
- Intrinsic upper airway obstruction due to masses is uncommon in pediatric age group
- Subglottic hemangioma is a common cause of neonatal respiratory distress and obstruction at subglottic level (Figs 7.30A to C)
- Intrabronchial mass (Figs 7.31A to D) that can cause luminal obstruction in children and adolescents include adenoma, carcinoid, papilloma etc.
Figs 7.29A to C: Stricture of left main bronchus following retreival of a metallic foreign body. Axial NCCT chest mediastinal (A) and lung (B) window reveal a metallic foreign body in left main bronchus (arrow) with complete collapse of the left lung. Coronal MinIp image of CT (C) acquired after bronchoscopic removal of the foreign body shows a short segment stricture (arrow) of the left main bronchus and a hyperlucent left lung secondary to air trapping.
Figs 7.30A to C: Subglottic hemangioma in a neonate. Axial SE T2W fat suppressed images at glottic level (A) is normal whereas image at subglottic level (B) shows a hyperintense intraluminal mass (block arrow). Sagittal contrast enhanced SE T1W fat suppressed image of the neck (C) shows the enhancing subglottic mass (block arrow) with luminal obstruction. The tracheostomy site is shown with an arrow.
Figs 7.31A to D: Intraluminal mass causing bronchiectasis in an adolescent male. Axial CECT chest mediastinal (A) and lung (B) window; coronal reformatted image mediastinal window (C) and coronal MinIP image (D) show an intraluminal mass in left main bronchus (arrow), causing near complete occlusion and extensive bronchiectasis of left lung.
Small Airway Abnormalities
- Diseases involving the small airways are different from those involving major airways
- Small airway inflammation (bronchiolitis) is a common manifestation of childhood viral respiratory infection
- Chest radiograph often normal, or may show hyperinflation
- CT reveals scattered areas of air trapping and centri-acinar nodules, with or without branching pattern (tree-in-bud appearance (Figs 7.32A to C)
- Chest radiograph in childhood asthma is usually normal
- Most common findings on chest imaging are hyperinflation, patchy air-trapping and centriacinar nodules due to mucoid impaction (Figs 7.33A and B)
- Post infectious bronchiolitis can produce similar imaging features
- Chronic bronchioloitis (Figs 7.34A to C) or bronchiolitis obliterans may show patchy air-trapping with peribronchial consolidation; and present with continuing respiratory distress or oxygen dependence in a child.
Figs 7.32A to C: Viral bronchiolitis in a child. Axial CECT chest lung window images reveal widespread patchy areas of air trapping in both the lungs (arrows).
Figs 7.33A and B: Bronchial Asthma. Axial CECT chest lung window images reveal widespread patchy areas of air trapping in both the lungs (arrows).
Normal
Thymus
- Children less than 5 years, quadrilateral shape on CT, with convex or straight lateral margins.
- Is usually triangular by 15 years of age.
- Lobulated margin of the thymus is abnormal.
- Is homogeneous in prepubertal children. The attenuation value matches that of skeletal muscle (Figs 8.1A to C).
- In adolescents it may be heterogeneous, because of interspersed areas of fat.
- Anatomic variations: can extend into the posterior mediastinum or upper neck.
- Clues in favor of diagnosis of a normal thymus over other mediastinal mass are:
- Absence of mass effect
- Anatomic contiguity with normal thymus
- Extension between superior vena cava and the trachea.
Lymph Nodes
- No well-established data regarding the size of normal lymph nodes in infants and young children. Mediastinal lymph nodes are usually not seen on CT in prepubertal children.
- Widest dimension of the nodes should then not exceed 1 cm.
- Recognizing this normal convexity towards right side is important in order not to misdiagnose it as lymphadenopathy.
Classification of mediastinal masses
Anterior Mediastinal Masses
- Lymphoma
- Thymic hyperplasia
- Thymoma
- Germ-cell tumors
- Thymolipoma
- Lymphangioma or cystic hygroma
Middle Mediastinal Masses
- Bronchogenic cysts
- Enteric foregut cyst
- Mediastinal lymphadenopathy
Posterior Mediastinal Masses
- Neuroblastoma
- Other neurogenic tumors (ganglioneuroma)
- Paravertebral abscess
- Neurenteric cyst
- Extramedullary hematopoiesis.
Anterior Mediastinal Masses
Lymphoma
- Most common cause of anterior mediastinal mass in children.
- Hodgkin lymphoma 3–4 times more frequent than non-Hodgkin lymphoma.
- Non-Hodgkin disease often spares the thymus (unlike Hodgkin disease)
- Imaging appearances may range from mildly enlarged nodes in a single area to large conglomerate nodal mass causing mediastinal vascular encasement (Figs 8.2 and 8.3).Figs 8.2A and B: Lymphoma. CT scout image (A) showing mediastinal widening, axial CECT chest image (B) showing homogeneous multicompartmental mediastinal mass encasing the great vessels.
- Lymph nodal mass shows minimal or no contrast enhancement.
- Calcifications or cystic areas can be seen.
- Lymph nodal mass causes airway and vascular compression.
Thymic Hyperplasia
- In childhood, rebound thymic hyperplasia is often associated with chemotherapy, particularly therapy with corticosteroids.
- Rebound thymic hyperplasia can be observed during or after completion of chemotherapy.
- On CT, hyperplasia seen as diffuse enlargement of the thymus (>50% increase in volume) (Figs 8.4A and B)
- Normal triangular shape is preserved.
- CT, MRI or PET cannot differentiate rebound thymic hyperplasia from thymic tumor.
- A gradual decrease in thymus size on serial imaging favors the diagnosis of rebound hyperplasia.
- The thymic size usually returns to normal in 3 to 6 months.
Thymoma
- Very rare
- Thymomas and thymic carcinomas account for a very small percentage of all mediastinal tumors in children.
Figs 8.4A and B: Thymic hyperplasia in a 12-year girl with myasthenia gravis. CT scout image (A) and CECT chest axial image (B) showing enlarged thymus with straight lateral borders.
Fig. 8.5: Anterior mediastinal mature teratoma. CECT chest axial image showing anterior mediastinal mass containing fat, calcification and soft tissue attenuation.
Figs 8.6A and B: Ruptured anterior mediastinal mature teratoma: Axial CT images of chest showing anterior mediastinal mass containing fat (arrow), soft tissue and calcification (A). A caudal section (B) shows ill-defined borders of the lesion with air specks in the wall and adjacent to the lesion (arrow). Air apecks in wall with consolidation in surrounding lung parenchyma suggests rupture into the adjoining lung.
Figs 8.7A and B: Malignant germ cell tumor: Chest Radiograph (A) showing mediastinal widening with multiple nodules in bilateral lung fields (arrows). Axial CECT image (B) of chest showing heterogeneously enhancing soft tissue attenuation mass lesion with areas of calcification. In addition, multiple lung nodules are seen suggestive of metastases (arrow).
- Second most common cause of anterior mediastinal mass in children.
- Most of the germ cell tumors are benign.
- On CT, a benign teratoma is seen as a well-defined, thick-wall cystic mass showing fatty, calcific and soft tissue attenuation.
- Benign teratoma shows minimal soft tissue component.
- Size is not a marker of malignancy.
- 10% of germ cell tumors are malignant. They show wall irregularity, and significant soft tissue component.
- Malignant tumors show pulmonary or liver metastases and chest wall invasion.
Thymolipoma
- A rare fat-containing thymic tumor.
- Usually asymptomatic.
- Imaging feature—heterogeneous mass containing fat and soft tissue elements. Calcifications are absent.
- No mass effect.
Lymphangioma or Cystic Hygroma
- Developmental tumors of the lymphatic system.
- In the mediastinum, they are almost always seen as an inferior extension of a cervical lymphangioma.
Figs 8.8A and B: Anterior mediastinal lymphangioma. Chest radiograph (A) and CECT chest (B) show a large anterior mediastinal mass of fluid attenuation, having thin enhancing septae within.
Figs 8.9A and B: Neck and anterior mediastinal lymphangioma. T2W axial MR image showing hyperintense lesion insinuating between the great vessels in anterior mediastinum (arrow).
- May encase vessels.
- Typically seen in infants younger than 6 months of age.
- MRI helps in better delineation of the extension of the lesion.
Thymic Cysts
- Congenital lesions resulting from persistent thymopharyngeal duct.
- Can also occur after thoracotomy.
- Imaging feature: Thin walled, homogeneous masses on CT.
- The attenuation value may be higher than that of simple cysts when the contents are proteinaceous or hemorrhagic.
Clues to Diagnosis
- Soft-tissue: Lymphoma, hyperplasia, germ cell tumor
- Water: Lymphangioma, thymic cyst
- Forget: Thymoma, thymic carcinoma, thyroid.
Middle Mediastinal masses
Bronchogenic Cysts
- Foregut cysts can be bronchogenic or enteric.
- Bronchogenic cysts: Lined by respiratory epithelium (Figs 8.10A and B). Common location—subcarinal or right paratracheal area in close proximity to the trachea or bronchus.
- Enteric cysts: Lined by gastrointestinal mucosa (Figs 8.11A and B). Common location—paraspinal position in the middle to posterior mediastinum near the esophagus.
Figs 8.10A and B: Bronchogenic cyst. Chest radiograph (A) and CECT axial soft tissue window image; (B) reveal a large middle mediastinal fluid attenuation lesion in the subcarinal location.
Figs 8.11A and B: Duplication cyst. Chest radiograph (A) shows opaque right hemithorax. CECT axial soft tissue window image (B) reveals a large cystic lesion in the middle and posterior mediastinum, with thick walls.
Mediastinal Lymphadenopathy
- Cause—lymphoma, granulomatous disease, metastasis.
- On CT, they can appear as discrete, round, soft tissue masses or as a single soft tissue mass with poorly defined margins (also see page no. 115).
- Intranodal calcification suggests old healed granulomatous disease, fungal infection or metastatic disease from osteosarcoma.
- Areas of low attenuation (necrosis) suggest tuberculosis or fungal infection.
Posterior Mediastinal masses
- Usually malignant in the first decade of life, most commonly neuroblastoma.
- Usually benign in the second decade of life (ganglioneuroma, neurofibroma, rarely schwannoma).
- Rarely, teratoma may arise in posterior mediastinal location (Figs 8.15A and B)
- Pott's spine with paraspinal abscess is seen on imaging as posterior mediastinal mass (Figs 8.16A and B).
Neuroblastoma
- Typically fusiform in shape, of soft tissue density; calcification seen in 50% of thoracic tumors.
Fig. 8.12: Posterior mediastinal neurogenic tumor. CECT chest axial soft tissue window image reveals a right sided posterior mediastinal well defined soft tissue mass.
Figs 8.13A to C: Posterior mediastinal neuroblastoma. Chest radiograph (A), CT chest axial images (B and C) reveal a left sided posterior mediastinal well defined soft tissue mass causing anterior displacement of the descending aorta, and destruction of the left sided 6th rib.
Figs 8.14A and B: Posterior mediastinal neurofibrosarcoma. Chest radiograph (A) and CECT chest axial soft tissue window image (B) reveal a right sided posterior mediastinal well defined soft tissue mass.
Figs 8.15A and B: Posterior mediastinal mature teratoma. Chest radiograph (A) shows opaque left hemithorax. CECT chest axial soft tissue window image (B) reveals a large transcompartmental mass on left side, having epicenter in posterior mediastinum and showing fatty, calcific and soft tissue attenuation within.
Figs 8.16A and B: Paravertebral abscess in a case of tuberculosis. CT scout (A) reveals a posterior mediastinal mass with displacement of the paraspinal lines. CECT chest (B) reveals the presence of a paraspinal abscess (arrow) with multiple splenic granuloma (block arrow).
- Extends over several interspaces; frequently invades the vertebral canal.
- CT shows a mass with calcification in the posterior mediastinum extending over several vertebrae, which shows extension into the vertebral canal.
- MRI is useful in delineating the invasion of the vertebral canal.
Other Neurogenic Tumors
- Ganglioneuroma, neurofibroma and rarely schwannoma.
- Round or oval in shape, smaller in size than neuroblastoma
- Usually extend over only one or two vertebrae.
Figs 8.17A to D: Neurenteric cyst. Chest radiograph PA and lateral view (A and B) reveal a posterior mediastinal mass with widening of the upper thoracic bony spinal canal. CECT chest axial image (C) and sagittal reformatted image (D) reveal the presence of a fluid attenuation mass in the posterior mediastinum and within the spinal canal.
Neurenteric Cyst
- Contain neural and gastrointestinal element.
- Commonly associated with vertebral anomalies and scoliosis (Figs 8.17A to D).
- Well demarcated; has a near water attenuation value on CT and water signal intensity on MRI.
Extramedullary Hematopoiesis
- Constitutes less than 0.1% of the lesions in the posterior mediastinum. Characterized by hematopoiesis outside of the bone marrow.
- Seen in patients with severe anemia.
- Imaging findings: paravertebral mass, in association with coarse bone trabeculations in the adjacent vertebra.
Multicompartmental Mediastinal Lesions
Figs 8.18A and B: Multicompartmental mediastinal lesion: Lymphoma Chest radiograph (A) showing mediastinal widening. Axial CECT chest image (B) showing extensive homogenous adenopathy involving all three compartments of mediastinum compressing the airway and encasing the mediastinal vascular structures.
Figs 8.19A to C: Multicompartmental mediastinal lesion, tuberculosis Chest radiograph (A) showing mediastinal widening. Axial CECT chest images (B and C) showing extensive necrotic adenopathy involving all three compartments of mediastinum and encasing the mediastinal vascular structures. Note evidence of necrosis within the mediastinal nodes (arrow).
Although the list of pathologies involving the chest wall overlap with those in the adult population, many of the chest wall lesions are unique to the pediatric population.
- Radiographs are the initial investigation performed
- Often followed by ultrasound (especially valuable)
- real-time ability to examine the patient
- CT or MRI for confirmation and further characterization of a chest wall lesion.
Classification
Congenital or Developmental Abnormalities
- Pectus excavatum
- Pectus carinatum
- Bone dysplasias.
Infection
- Bacterial infection
- Tuberculosis
- Fungal infection
- Chronic recurrent multifocal osteomyelitis.
Trauma
Metabolic
- Rickets
- Scurvy.
Hematological
- Hemolytic anemias.
Storage Disorders
- Mucopolysaccharidosis, mucolipidosis.
Neoplasms
Benign Osseous Tumors
- Osteochondroma
- Fibrous dysplasia
- Mesenchymal hamartoma.
Malignant Soft-tissue Tumors
- Rhabdomyosarcoma
- Pleuropulmonary blastoma
- Ewing sarcoma family of tumors.
Metastatic Disease (Most Common)
- Neuroblastoma
- Rhabdomyosarcoma
- Lymphoma or leukemia.
Congenital or Developmental Abnormalities
Pectus Excavatum
- Depression of the sternum relative to the rest of the anterior chest (Figs 9.1A to C)
- In most case deformity is purely cosmetic
- Severe cases can result in pain, dyspnea, and restrictive lung disease, RA compression
- Anterior indentation and deformity of right ventricle
- Heart may be rotationally displaced into the left hemithorax
- Mitral valve prolapsed might result from the deformity of mitral valve annulus
Figs 9.1A to C: Pectus excavatum. NCCT thorax axial soft tissue window image (A), sagittal reformatted (B) and volume rendered image (C) reveal depressed sternum causing compression and displacement of the heart. The Haller index was 5.6.
- Reduced thoracic antero-posterior diameter can result in compression of trachea leading to tracheomalacia
- A pseudoinfiltrate to the right of the cardiac silhouette related to greater visibility of the hilar vessels and displacement of cardiac silhouette to the left
- The sternal depression can be directly visualized on the lateral radiograph
- Quantify the severity by the Haller index (maximal transverse diameter of chest/AP diameter from vertebral body to the sternum)
- < 2.56 is considered normal; > 3.25 often requires surgical correction
Pectus Carinatum
- Anterior protrusion of the sternum (Figs 9.2A and B)
- Male predominance
- Associations—Marfan disease, Noonan syndrome, Prune belly, Morquio syndrome, osteogenesis imperfecta, mitral valve prolapse, homocystinuria, rickets
Figs 9.2A and B: Pectus carinatum in a 10-year-girl child. Lateral chest radiograph (A) and axial CT chest show the anterior protrusion of lower sternum.
Fig. 9.3: Thin ribs with osteopenia in osteogenesis imperfecta. Note multiple rib fractures (arrows).
- Can manifest clinically as shortness of breath and exercise intolerance
- Increased anteroposterior diameter of the chest and anterior protrusion of the sternum
- Haller index <1.98.
Bone Dysplasias
- Dysplasia with decreased bone density
- Osteogenesis imperfecta (Fig. 9.3)
- Dysplasia with increased bone density
- Osteopetrosis
- Pyknodysostosis
Figs 9.4A and B: Cleidocranial dysostosis in a 5-year-male child. Chest radiograph (A) shows hypoplastic lateral end of right clavicle. The hand radiograph (B) shows resorption of the distal phalanges and increased bone density. - Short ribs dysplasia
- Short rib polydactyly syndrome
- Ellis-van Creveld syndrome
- Jeune syndrome
- Dysplasia with thin ribs
- Osteogenesis imperfecta
- Dysplasia with narrow thorax
- Thanatophoric dysplasia
- Asphyxiating thoracic dyplasia (Jeune syndrome) (Fig. 9.5)
- Campomelic dysplasia
- Short rib polydactyly syndrome.
Infection
Bacterial Infection
- Rare condition that typically involves the ribs or sternum
- Most typically due to Staphylococcus aureus
- Clinical findings of acute infection
- Radiograph only after 7–10 days, consists of rib destruction, periosteal reaction, and overlying soft-tissue swelling
- CT or MRI remain the preferred imaging modalities.
Tuberculosis (Discussed in the Chapter 6)
- 1 and 2% of the total cases of tuberculosis
- Sternum, sternoclavicular joints, ribs and spine
- Spine being the most frequent site with multilevel involvement; showing disk space loss, vertebral destruction, and paraspinal abscesses.
Fungal Infection
- Immunocompromised patient population
- Aspergillus species account for up to 80–90%
- Ribs involved by direct extension from an underlying pulmonary process
- Imaging characteristics are nonspecific
- Made in the appropriate clinical context and confirmed by either culture or histopathology.
Trauma
Accidental Trauma
- Fracture of the ribs and sternum occurs less frequently due to elasticity of the pediatric chest wall
- Metabolic bone diseases may predispose the patient to fracture, such as rickets or osteogenesis imperfecta.
Nonaccidental Trauma
- Combination of clinical history and imaging findings
- Absence of major trauma, fractures of the ribs suggest nonaccidental trauma
Metabolic
Rickets
- Rachitic rosary
- Expansion of the anterior rib ends at the costochondral junctions (Figs 9.6A to C)
- Pectus carinatum
- Harrison's sulcus—indrawing of the lower ribs.
- As many patients with rickets suffer from protein-energy malnutrition as well, some patients might have lung parenchymal changes secondary to impaired immune response (Fig. 9.6D).
Scurvy
- Scorbutic rosary
- Costochondral junction is more angular and has a sharper step-off
- May relate to fracturing of the zone of provisional calcification during normal respiration.
Figs 9.6A to C: Rickets. Chest radiograph (A) and CECT chest (B) show flared anterior ends of the ribs. Fibroparenchymal lesions are seen in upper zones of bilateral lung fields. Radiograph of the wrist reveals flaring, cupping and fraying of the distal radial and ulnar metaphyses. Figure D shows lung parenchymal changes in form of peripheral consolidation.
Hemolytic Anemias
- Bilateral paraspinal masses with round, lobulated margins
- Thoracic masses occur most often in patients with thalassemia or congenital hemolytic anemia
- Medullary expansion of the bony structures with widening of the ribs is most pronounced
- Resorption of trabeculae produces coarsened appearance to bones
- H-shaped vertebrae/vanishing vertebra—infarction in sickle cell disease.
Neoplasms
Osteochondroma
- Osseous protuberance in continuity with the surface of the originating bone
- Sessile or pedunculated
- CT is superior to radiography for showing the characteristic continuity of the cortex and medullary cavity with the osteochondroma
- Cartilage cap (if calcified) can sometimes be seen on CT, but this structure is better visualized on MRI.
Mesenchymal Hamartoma
- Lesion develops during fetal life, and is present at or shortly after birth
- Expansile intraosseous overgrowths of normal skeletal elements, including bone and hyaline cartilage
- Expansile chest mass that involves one or more ribs (Figs 9.7A to D)
- Speckled popcorn like calcifications
- Secondary aneurysmal bone cyst formation showing fluid-fluid levels on imaging
- Self-limited lesions that typically stop growing within the first year of life
- Imaging features characteristic
- Biopsy findings are variable, seldom diagnostic
- Surgery indicated only in case of pressure symptoms.
Fibrous Dysplasia
- Typically asymptomatic and found incidentally
- Monostotic or polyostotic depending on the number of lesions
- Focal well-defined expansile intramedullary lesion with a ground-glass matrix
- CT can detect amorphous calcifications within the lesion
- On MRI typically is isointense to skeletal muscle on T1-weighted images and heterogeneously hyperintense on T2-weighted sequences and shows heterogeneous enhancement in active stage.
Rhabdomyosarcoma (also see Chapter no. 13)
- High-grade mesenchymal tumors
- Rapidly growing and painful
- Bone involvement is less frequent and occurs later
- Ultrasound shows a well-defined mass
Pleuropulmonary Blastoma
Discussed in the Chapter 13.
Ewing Sarcoma Family of Tumors
- Slight male predominance, most are diagnosed within the second decade of life
- High-grade small round cell tumors
- Ewing sarcoma (Figs 9.8A and B), atypical Ewing sarcoma, peripheral primitive neuroectodermal tumor (Figs 9.9A and B) and Askin tumor (shared chromosomal translocation)
- Rapidly growing chest wall masses, pain, neurologic symptoms, and fever
- Extrapleural mass with prominent bone destruction and aggressive characteristically lamellated periosteal reaction
Figs 9.8A and B: Ewing's sarcoma arising from the right-sided 6th rib. CT scout image (A) shows permeative destruction of the right 6th rib posterior aspect (arrow) with opaque right hemithorax. CECT chest (B) reveals the large solid mass filling the right hemithorax. Another patient with PNET arising from vertebral body shows paravertebral soft tissue widening on AP radiograph (c) and collapse of dorsal vertebra (d). Axial CECT image shows pre and paravertebral soft tissue mass.
Figs 9.9A and B: Left sided 10th rib PNET. CT scout image (A) and CT axial image (B) show a sclerotic left 10th rib posterior end (arrow), with a large calcified extrapleural soft t issue mass.
- Suspect in young patient with chest wall origin mass and single rib destruction
- Bone erosions seen secondary to soft tissue mass/metastasis—multiple rib involvement
- CT is helpful for identifying bone destruction not visible on radiographs, as well as the full extent of cortical involvement of the tumor and lung metastases.
Metastatic Disease
- Most common malignant chest wall tumor
- Imaging appearance of metastatic disease involving the chest wall is often nonspecific
- Typically presents as lytic lesions with overlying cortical disruption
- Neuroblastoma, Rhabdomyosarcoma, Lymphoma or leukemia.
- Involvement of pleura is mostly secondary to lung or chest wall pathology
- Effusion is the most commonly encountered abnormality
- Ultrasound has an important role in the evaluation of pleural abnormalities.
Classification of Pleural pathologies
- Effusion
- Transudate/serous pleural effusion:
- CHF, hypoprotenemia (malnutrition, nephrotic syndrome, chronic liver disease)
- Exudative effusion:
- Infective—synpneumonic effusion, empyema (bacterial, tubercular, fungal)
- Neoplastic—malignant tumors of lung and chest wall, pleural metastases
- Chylous/pseudochylous:
- Neonatal tuberculosis
- Filariasis
- Pneumothorax
- Pneumatocoeles—Staphylococcus, PCP pneumonia
- Mechanical ventilation
- Trauma
- Primary pleural neoplasm
- Pleuropulmonary blastoma (Chapter 13)
- Pleural deposits
- Lymphoma
- Germ cell tumor.
Effusion
Transudate/Serous Pleural Effusion
- Clear fluid
- No internal echoes on ultrasound
- No loculations
- Concave upper border (meniscus sign) on erect radiographs in free effusion (Fig. 10.1)
- Increased opacity of hemithorax, apical cap, widening of mediastinum on supine radiograph
- Underlying lung generally normal; basal atelectasis may be seen
- No enhancement of pleura on CECT.
Exudative Pleural Effusion/Empyema
- Internal echoes on USG
- Loculations and septations
- Split pleura sign
- Underlying lung parenchymal abnormality.
Chylous/Pseudochylous Effusion
Neonatal Chylothorax
- Causes
- Rupture of thoracic duct due to hyperextension of spine (birth injury)Fig. 10.1: Free pleural effusion in a 15-year-old girl. Left CP angle is blunted, the left lower zone opacity has a concave upper margin (the meniscus sign).Figs 10.2A and B: Chest radiograph (A) and CT chest (B) showing left-sided empyema. Note the enhancing pleural margins/split pleura sign (arrow) and the fluid in pleural space on left side.Fig. 10.3: Split pleura sign in empyema. Note the enhancing pleural margins (arrow) and the fluid in pleural space on right side.133Figs 10.4A and B: Right sided empyema thoracis. CT chest reveals the pleural fluid collection (A), which was subsequently drained with a self-retaining catheter under CT guidance (B).
- Congenital malformations of thoracic duct
- Turner syndrome, Noonan syndrome
- Iatrogenic (open heart surgery)
- Neonatal tuberculosis also has been described
- Low density effusion on CT with fat-fluid levels
Pneumothorax
- Hyperlucent hemithorax (Fig. 10.5)
- Visible visceral pleural outline (Figs 10.6A to C)
- Lack of bronchovascular markings in peripheral fields
- Deep sulcus sign on supine radiograph
- Bar code sign on USG
- Flattening of diaphragm/mediastinal shift—Tension pneumothorax
- Loculated pneumothorax shows well-defined margins (Figs 10.7A to C).
Neonatal Pneumothorax
- Causes
- Idiopathic
- Secondary to lung abnormalities
- Respiratory distress syndrome
- Meconium aspiration
- Pneumonia with pneumatocoeles
- Vigorous resuscitationFig. 10.5: Pneumothorax evidenced by a hyperlucent left hemithorax, visualization of the visceral pleural margin (arrow) and the collapse of underlying lung.Figs 10.6A to C: Spontaneous pneumothorax in a case of apical bulla in right lung. CT chest scout (A), axial (B) and coronal reformatted (C) images show the air in the pleural space and the visceral pleural margin (arrow).Figs 10.7A to C: Loculated hydropneumothorax in a 10-year boy. CT scout (A), and axial lung window images (B and C) reveal free as well as loculated left pneumothorax.Figs 10.8A to F: Images from two different patients showing large air filled loculated spaces in right hemithorax. Patient 1(A to C), Patient 2(D to F). Previous imaging (C) of patient 1 shows an area of consolidation with cavitation suggesting subsequent evolution into an abscess. In patient 2 with loculated pneumothorax (D and E) there is no change compared to the previous scan (F).
- Positive pressure ventilation
- Lung hypoplasia
- CCAM
- Always rule out a skin fold when pneumothorax is suspected in neonates
- USG is a handy tool for detection of pneumothorax in ICU settings
Loculated Pneumothorax Vs Large Lung Abscess
The distinction between these two entities may be very problematic at times. Previous imaging, if available, may be helpful in such situations; which would show a consolidation in patients with cavitation (Figs 10.8A to E).
Neoplasms
- Pleural neoplasms can be primary or secondary
- Primary Pleuro-pulmonary blastoma has been described in chapter 13
Pleural Deposits
- Soft tissue nodules or masses along the pleura
- Contiguous extension in lymphoma (Figs 10.9A and B) and metastases from a mediastinal germ cell tumor
- Associated exudative pleural effusion.
Interstitial lung diseases refer to uncommon diseases involving the lung parenchyma with impaired gas exchange. As these may involve not only the pulmonary interstitium but also the airways or alveoli the term diffuse lung diseases (DLDs) is more appropriate. Due to the superimposition of pathology on an underlying developing lung DLDs in children are significantly different compared to adults. These are also less common in children than in adults, and more common in infants and young children than in older children. Also, DLDs in children are seldom idiopathic, usually having an underlying etiology. The etiology is often congenital presenting in infancy.
Classification
Interstitial lung diseases or diffuse lung diseases in children can be considered as two broad groups: those that are common to adults and those entities which are peculiar to children. Diagnosis of the type of ILD is a combined clinical-radiographic-pathologic diagnosis, based on the radiohistological pattern (Table 11.1) and underlying etiology if any.
Radiologic-Histological Patterns
Children Versus Adults
- NSIP, LIP and DIP are seen in children
- Underlying etiology and pathogenesis of NSIP, LIP and DIP is different
- Usual interstitial pneumonia (UIP) as seen in adults and causing idiopathic pulmonary fibrosis is not seen in children
- DIP patterns—noted in genetic surfactant disorders
- LIP pattern—noted in immunodeficiency syndromes, lipoid pneumonia (Inborn errors of metabolism)
- NSIP pattern—noted in underlying autoimmune disease, hypersensitivity pneumonitis, surfactant protein deficiency
- Alveolar proteinosis—found in genetic surfactant disorders (Surfactant protein B deficiency).
The other method of classification is to divide them according to the underlying cause (Table 11.2).
Another new system of classification (Table 11.3) was developed jointly by the clinicians, pathologists and radiologists in the Children's Interstitial Lung Disease (ChILD) Research Cooperative based on a retrospective review of 186 lung biopsies (1999–2004) in North America.
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Specific entities and patterns
Diffuse Developmental Disorders
- Include acinar dysplasia, congenital alveolar dysplasia (CAD) and alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV)
- All entities fatal in infancy
- Present usually within 48 hours after birth
- Lack specific radiographic abnormalities
- CAD and ACD/MPV have high association with congenital cardiovascular, gastrointestinal and genitourinary abnormalities
- CXR: Normal to low lung volume, diffuse hazy opacity resembling surfactant deficiency disorders
- Prone to develop pulmonary artery hypertension early in life.
Alveolar Growth Abnormalities
- Lung pathology occurs as a result of superimposed events, either pre-natal or postnatally
- Prenatal condition leading to pulmonary hypoplasia—polyhydramnios, congenital diaphragmatic hernia
- Postnatal insult—bronchopulmonary dysplasia (BPD)
- Clinical presentation variable
- Imaging findings variable, few entities having specific imaging features (e.g. BPD, Trisomy 21)
- BPD—affects premature infants, present with chronic lung disease and oxygen dependence
- Imaging in BPD—coarse reticular opacities, cystic lucencies
- Trisomy 21—peripheral subpleural cysts
- ILD associated with congenital heart disease can present with mosaic attenuation (Figs 11.1A to D) due to ground-glass opacities and altered lung vascularity.
Genetic Surfactant Dysfunction Disorders and Related Diseases
- Inborn errors of surfactant metabolism are a group of uncommon disorders resulting from genetic mutations involving surfactant proteins141Figs 11.1A to D: ASD with pulmonary artery hypertension and mosaic attenuation in the lungs. Axial CECT of chest soft tissue (A and B) and lung window (C and D) images reveal enlarged main pulmonary artery and cardiomegaly; areas of mosaic attenuation owing to ground-glass opacities in both lungs; and septal thickening.
- Clinical, radiographic and histologic pattern of presentation vary according to the type of gene mutation
- Radiologic patterns in infants include: Pulmonary alveolar proteinosis (PAP), chronic pneumonitis of infancy (CPI), desquamative interstitial pneumonia (DIP)
- Radiologic patterns in older children and adolescents: NSIP and UIP.
Surfactant Protein B Deficiency
- Age of presentation—neonates
- Fatal, presents with neonatal respiratory distress and respiratory failure
- Chest radiographic findings resemble respiratory distress of prematurity
- HRCT pattern—PAP.
- Age of presentation—neonates, infants or older children
- Imaging pattern—PAP or DIP in neonates and young infantsFigs 11.2A to D: Surfactant protein deficiency in a 6-month-old infant presenting with PAP pattern. Chest radiograph PA view (A) shows ‘whiteout lung’. Axial CT of the chest lung window (B) reveals extensive consolidation in both lungs and areas of ‘crazy-paving’. Follow-up imaging (C and D) after three months show significant resolution of the consolidation with residual ground-glass opacities.
- NSIP pattern with areas of lipoid pneumonia like picture in older children.
Surfactant Protein C Deficiency (Figs 11.4A to C)
- Age of presentation—older infants, children, adults.
- Imaging pattern—CPI in older infants—chronic interstitial pneumonia and pulmonary fibrosis in older children, adults.
Specific Conditions of Unknown or Poorly Understood Etiology
Neuroendocrine Cell Hyperplasia of Infancy (NEHI)
- Histopathological entity with clinical correlate of syndrome of persistent tachypnea of infancy
- Term infants who present with tachypnea, hypoxia, crackles and retractions; not responding to steroids or bronchodilators
- Pathogenesis is not clear—genetic/acquired
- Histopathology: Lung biopsy almost normal on routine H and E stain/nonspecific, mild airway wall abnormalities. Immunohistochemistry—increased neuroendocrine cells in airway wall
- Chest radiographs: Hyperinflation
Figs 11.4A to C: Surfactant dysfunction disorder in a 2-year-old girl. Chest radiograph PA view (A) shows bilateral consolidation involving the central lung fields. Axial CT of the chest lung window (B and C) reveal extensive ground-glass opacities, septal thickening and dependent consolidation in both lower lobes.
Cellular Interstitial Pneumonitis/Pulmonary Interstitial Glycogenosis (PIG)
- Also called infantile cellular interstitial pneumonia (ICIP) or cellular interstitial pneumonitis of infancy. It is different from cellular pneumonitis of infancy (CPI)
- Probably a reactive condition of developing lung
- Often seen in association with other pathologies such as meconium aspiration and adjoining congenital anomalies
- Presentation—tachypnea since birth
- Good prognosis with improvement seen over time
- Histopathology: Resembles CPI with increased cellularity of the interstitium. Electron microscopy shows primitive interstitial cells with abundant cytoplasmic glycogen
- Chest radiographs—nonspecific with diffuse lung infiltrates.
Chronic Pneumonitis of Infancy
- Not included in the new classification system
- Histopathology: Alveolar exudates with numerous macrophages, alveolar septal thickening, pneumocyte hyperplasia
- Chest radiographs: Extensive ground-glass opacities, areas of fibrosis, volume loss or hyperinflation.
Interstitial Lung Diseases (ILDs) Secondary to Underlying Diseases
Immune-mediated/Collagen Vascular Disorders
- Common histologic/radiological patterns include follicular bronchiolitis, NSIP or LIP
- Pleural effusion, thickening or fibrosis may also be seen.
- Underlying disorders include progressive systemic sclerosis (PSS), dermatomyosistis, juvenile idiopathic arthritis and Sjögren syndrome. The frequency of the pattern differs according to the underlying disease (Table 11.4).
Follicular Bronchitis/Bronchiolitis (Figs 11.7A to C)
- Infants presenting with tachypnea, fine crackles, and chronic cough by the age 6 weeks
Table 11.4 ILD associated with collagen-vascular disorders Collagen vascular disorderILD patternPSSNSIP, interstitial fibrosis (Figs 11.5A and B), pulmonary artery hypertensionDermatomyositisLIP, interstitial fibrosisJuvenile idiopathic arthritisLIP, chronic bronchiolitisSjögren syndromeLIP, chronic bronchiolitisWegener's granulomatosisNodules, consolidation (Figs 11.6A and B)145Figs 11.5A and B: UIP pattern in a 17-year girl with SLE. Axial CT of the lungs reveal interlobular septal thickening with a peripheral and basal predominance, microcystic honeycombing (arrow) and areas of traction bronchiectasis in left lower lobe (small arrow). - Good prognosis, patients improving gradually over several years
- Histopathology: Follicular lymphocytic infiltration involving the bronchial walls
- Imaging appearance is similar to NEHI, but biopsy findings are different as airway inflammation is not a prominent finding in NEHI. Also neuroendocrine cells are not seen in follicular bronchiolitisFigs 11.6A and B: Wegener's granulomatosis in a 14-year girl. Imaging findings on HRCT chest (A and B) include multifocal nodules and consolidation. Note the ‘reverse halo sign’ in B, evidenced by peripheral dense consolidation and central ground-glass opacities (arrow).Figs 11.7A to C: Follicular bronchiolitis. Chest radiograph PA view (A) shows bilateral hyperinflated lungs. Axial CT of lungs (B and C) reveal areas of air trapping (evidenced by attenuated vascular markings) and multiple small centriacinar nodules (arrows in C).
- Chest radiographs, CT: Similar to NEHI.
LIP (Figs 11.8A to C)
- Lymphocyte infiltrative disorders have a continuum of morphologic findings—follicular bronchitis/bronchiolitis (localized) to LIP (more diffuse)
- LIP associated with EBV and HIV infection
- HIV in children—30% acquire LIP (2nd to 3rd year)
- HRCT findings—nodules, GGO, peribronchovascular cysts, lymphadenopathy.
Infections
Bacterial Pneumonia
- Presents with lobar consolidation
- Interstitial pattern not commonly seen.
Pneumocystis Pneumonia (Figs 11.9A and B)
- Affects immunocompromised host
-
Figs 11.9A and B: Pneumocystis pneumonia with PIE. Axial CT images of lung reveal diffuse ground-glass opacity (A and B). PIE is evidenced by extension of air lucencies surrounding the pulmonary vessels (arrows in B). Note the ‘black bronchus sign’; described as prominence of the bronchial air in the background of GGO (block arrows in A).
- Presentation—respiratory distress, hypoxia
- CT—perihilar or diffuse GGO, consolidation, pneumatocele
- Complications—pulmonary interstitial emphysema (PIE), pneumothorax, pneumomediastinum.
Tuberculosis
- ILD unusual imaging feature of tuberculosis
- Mediastinal fibrosis secondary to tuberculosis can cause lymphatic obstruction, giving rise to smooth septal thickening on HRCT (Figs 11.10A to F).
Malignancy
- Malignant mediastinal lymphadenopathy can give rise to lymphatic obstruction and smooth septal thickening on HRCT
- Lung interstitium involvement in Hodgkin's lymphoma usually secondary to mediastinal and hilar lymphadenopathy and contiguous peribronchovascular extension (Figs 11.11A to D).
- Primary lung interstitium involvement commoner in NHL than Hodgkin's lymphoma and more in relapse rather that primary diagnosis.
Hypersensitivity Pneumonitis (HP)
- Similar to adults, HP in children is related to environmental exposure to antigens
- Common exposures in children are often related to bird or fungal antigens, unlike occupational exposure in adults
Figs 11.10A to F: Pulmonary lyphangiectasia and tubercular mediastinal lymphadenopathy. Chest radiograph PA view (A) reveals cardiomegaly with sharp cardiac outline, suggesting pericardial effusion. Axial CECT of chest soft tissue (B) window reveals low density mediastinal lymph nodes and hypodense sheet like mediastinal soft tissue (arrow) surrounding the vessels. Lung window image (C) reveals smooth interstitial septal thickening. Follow-up imaging after 6 months reveal extensive reticulonodular shadows in both the lungs on chest radiograph (D), increase in pericardial effusion and the septal thickening (F).
Sarcoidosis (Figs 11.12 and 11.13)
- Age group—late childhood and adolescents
- Imaging features—similar to adult sarcoidosis; hilar and mediastinal adenopathy, peribronchovascular nodules, irregular septal thickening
- Alveolar sarcoid shows consolidation on CT
- Advanced stage—interstitial fbrosis.
Langerhan's Cell Histiocytosis (LCH)(Figs 11.14 to 11.17)
- Pulmonary LCH seen approximately in 10% of children affected with multisystem disease
- Majority of childhood pulmonary LCH have systemic involvement, unlike adult pulmonary LCH
- Systemic features include ear discharge, mastoiditis, skeletal involvement, hepatobiliary involvement, maculopapular rashes, exophthalmos, diabetes insipidus secondary to pituitary stalk involvement, etc.
Figs 11.11A to D: Interstitial lung disease in non-Hodgkin lymphoma. Axial CECT of chest soft tissue window (A and B) and lung window (C) reveal enlarged homogeneous lymph nodes in right paratracheal, right hilar and subcarinal locations (arrow); with high-density consolidation extending along the peribronchovascular interstitium contiguous with the lymph nodes. Follow-up axial CT of the lungs (D) after 6 months show development of interstitial fibrosis and traction bronchiectasis in the location of previous lymphomatous involvement.
Figs 11.12A to C: Sarcoidosis in a 7-year male. Axial unenhanced CT of chest (A) reveals bilateral hilar adenopathy (block arrows). Axial CT of the lungs (B and C) show peribronchovascular nodules in right upper lobe (arrow) and left lower lobe.
Figs 11.13A to C: Sarcoidosis in a 11 year-old-girl. Frontal chest radiograph (A) reveals extensive reticulonodular shadows involving both lungs. Axial CT of the lungs (B) reveals ground glass opacities, septal thickening and ill-defined acinar nodules. Axial CECT of abdomen (C) reveals hepatosplenomegaly and small focal hepatic lesions (granuloma).
Figs 11.14A to C: LCH in a newborn. Axial CT of lungs (A and B) show extensive ground-glass opacities in bilateral lungs and scattered cysts (arrow). Axial image of high resolution CT of the inner ear (C) shows bilateral otitis media (block arrows).
Figs 11.15A to C: LCH in a 11-month-old boy. Axial CT of lungs (A and B) show multiple small cysts in bilateral lungs (arrow), and GGO involving the lower lobes (C).
Figs 11.16A to D: LCH in a 3-year-old boy. Axial CT of lung (A and B) and coronal reformatted image (C) show multiple irregular thin-walled cysts involving both the lungs without any zonal predominance. Follow-up CT after 1 year reveals progression of the cysts (D) (arrow).
Figs 11.17A to D: Multisystem LCH in a 14-month-old male child. Chest radiograph PA view (A) shows increased lung volumes and reticular opacities. Axial CT of chest lung window (B) shows extensive cystic changes involving bilateral lungs. Axial CECT of abdomen (C) reveals periportal hypodensity (arrow) which appears hypoechoic on ultrasound (D).
- Hepatobiliary involvement—periportal hypodensity (echogenic on US), focal hepatic lesions, sclerosing cholangitis
- Contrary to adult LCH, childhood pulmonary LCH has no upper lobe predilection
- Not associated with smoking
- CT findings—irregular nodules which tend to cavitate and form thin-walled irregular cysts, interstitial fibrosis
- Pneumothorax is a frequent complication.
ILD Secondary to Cardiovascular Surgeries
- May accompany surgery for congenital heart diseases
- Imaging findings may mimic localized mediastinal fibrosis (Figs 11.18A to C).
Miscellaneous
Idiopathic Pulmoanry Hemosiderosis (Figs 11.19A and B)
- A cause of diffuse pulmonary hemorrhage in children154Figs 11.18A to C: Acute interstitial pneumonia after surgery for total anomalous pulmonary venous return (TAPVC). Axial CECT of chest (A) reveals dilated main pulmonary artery suggesting pulmonary artery hypertension. Axial CT lung window images (B and C) shows multifocal consolidation and patchy ground-glass opacities.
- Other common cause of diffuse pulmonary hemorrahge in children—Goodpasture syndrome
- Age—usually under 10 years; both sex equally affected
- Etiology—unknown; autoimmune theory and sensitivity to cow milk protein proposed
- Presentation—cough, dyspnea, fever, pallor, hematemesis/hemoptysis
- Acute pahse—acinar nodules/consolidation, GGO
- Chronic phase—interstitial thickening and fibrosis
- Acute hemorrhage—imaging findings revert to normal within 2 weeks.
Pulmonary Alveolar Microlithiasis (Figs 11.20A and B)
- Rare disease of unknown etiology
- Deposition of calcium phosphate microliths in the alveoliFigs 11.19A and B: Idiopathic pulmonary hemosiderosis in a 15-year-old male child presenting with anemia. Frontal chest radiograph (A) shows diffuse ground-glass haziness involving both the lungs. Axial CT of chest lung window (B) shows presence of diffuse ground-glass opacity, septal thickening and areas of consolidaion in right lower lobe.155Figs 11.20A and B: Pulmonary alveolar microlithiasis. Chest radiograph frontal view (A) shows extensive high density nodules involving both lungs. Axial CT of chest lung window (B) shows extensive acinar nodules and nodular thickening of left-sided major fissure.
- May be inherited as autosmal recessive trait
- Early imaging findings—multiple small high density alveolar nodules
- Advanced stage—extensive nodules coalescing to give rise to high density consolidation, obscuring the heart borders on X-ray, widespread nodules with sparing of subpleural lung giving rise to a subpleural black line on HRCT.
End-stage ILD (Figs 11.21A and B)
- A large number of childhood ILD remain unclassified
- Causes—end-stage ILD with extensive fibrosis, insufficient biopsy sample, improper area selection for sampling
- Imaging features—fibrosis, traction bronchiectasis, volume loss.
Common causes of immunosuppression can be divided into congenital and acquired abnormalities.
Classification
Congenital
- Predominantly humoral (B-cell) disorders
- X-linked agammaglobulinemia (Bruton's a gammaglobulinemia)
- Common variable immunodeficiency (CVID)
- IgA deficiency
- Hypogammaglobulinemia
- Hyper IgM syndrome
- Combined B cell and T- cell disorders
- Severe combined immunodeficiency (SCID)
- Partial combined immunodeficiency syndromes
- Wiskott-Aldrich syndrome
- Cartilage-hair hypoplasia
- Ataxia telangiectasia
- X-linked lymphoproliferative disease
- Predominantly T cell disorders
- Thymic hypoplasia or aplasia/ DiGeorge syndrome
- Granulocyte disorders
- Chronic granulomatous disease
- Chediak-Higashi syndrome
- Leukocyte adhesion deficiency
- Complement disorders
- Complement component deficiencies
- Abnormal mucociliary clearance
Acquired
- Malnutrition (combined T and B-cell)
- Aplastic anemia
- Acquired immunodeficiency syndrome (T-cell)
- Hematologic malignancy such as leukemia and lymphoma (granulocyte- most prominent)
- Transplantation (immediate post-transplant phase- granulocyte; late phase- T-cell)The clinical indicators towards a primary immunodeficiency disorder in children include:
- Recurrent ear infections, sinus infections, pneumonia
- Recurrent deep seated skin or organ abscess, or septicemia
- Failure to gain weight, need for intravenous antibiotics to clear infections
- Persistent fungal infections
- Family history of primary immunodeficiency
Immunocompromised hosts may suffer from recurrent pulmonary infections due to common as well as opportunistic pathogens. The type of infection depends on the mechanism of immunodeficiency, irrespective of the primary or secondary nature of immunodeficiency (Table 12.1).
Bacterial infections have features similar to pneumonia seen in general population. Only clue to the underlying immunodeficiency is their recurrent and more severe nature. Only the diseases that are specific to immunodeficiency disorders are described in this chapter.
|
CONGENITAL ABNORMALITIES
Common Variable Immunodeficiency (CVID) (Figs 12.1A to C)
- Absent or very low circulating antibodies, B cell number normal
- Recurrent sinopulmonary infections, meningoencephalitis in late childhood or adulthood
- Splenomegaly and lymphadenopathy, lymphoid hyperplasia of the gastrointestinal (GIT), generalized lymphoproliferative disorders
- Prone to develop interstitial lung disease (ILD), bronchiectasis and lymphoreticular malignancies.
X-linked Agammaglobulinemia (Bruton'sag agammaglobulinemia)
- Absent circulating antibodies, reduced number of circulating mature B cells
- Late infancy or early childhood recurrent sinopulmonary infections, enteroviral meningoencephalitis, intestinal giardiasis
- Imaging: Middle and lower lobe bronchiectasis, typically small adenoids (and other lymphoid tissues)
Figs 12.1A to C: Common variable immunodeficiency. Infant presenting with recurrent chest infections. CT thorax soft tissue (A) and lung window images (B and C) reveal bilateral upper lobe collapse, and multiple patchy acinar nodules in both lower lobes; along with early bronchiectasis (arrow).
Figs 12.2A to D: IgA deficiency. CT scout film (A) of the infant shows multiple areas of patchy consolidation in both the lungs. CECT chest axial soft tissue and lung window images (B to D) reveal multiple patchy consolidation and septal thickening in both upper lobes.
Figs 12.3A to C: Congenital hypogammaglobulinemia with recurrent chest infections. CT scout film (A) reveals bilateral hyperinflated lung fields, CT chest axial lung window images (B and C) reveal bilateral diffuse peribronchial thickening in both the lower lobes (arrow).
IgA Deficiency (Figs 12.2A to D)
- Most common primary immunodeficiency disorder
- Prone to respiratory and GIT disorders, allergy and autoimmune disorders.
Combined T Cell and B Cell Disorders
T cell disorder is almost always associated with abnormality in antibody production (B cell response). All are characterized by severe viral infections, systemic fungal infections and parasitic infections.
DiGeorge Syndrome
- Failure of development of the third and fourth pharyngeal pouches
- Absent thymus, dysmorphic facies
- Tetany (resulting from lack of the parathyroids)
- Congenital defects of the heart and great vessels.
Severe Combined Immunodeficiency (SCID)
- Group of disorders characterized by absent T cell and B cell function (NK cells may also be affected)
- Failure to thrive, chronic diarrhea, rashes, oral thrush, sepsis since early infancy
- ADA deficiency subtype: Characteristic skeletal imaging, flared anterior costochondral junctions, metaphyseal cupping, squaring of scapular tip, ‘bone in bone’ appearance of vertebral bodies
- Chest imaging: Recurrent or severe pneumonia
- Treatment: Bone marrow transplant.
Wiskott-Aldrich Syndrome
- Triad: Eczema, thrombocytopenia (small defective platelets), recurrent infections
- Complications: Massive bleed, infection, lymphoreticular malignancy.
Phagocytic Disorders (Disorders of Granulocyte, Monocyte, Macrophages)
Chronic Granulomatous Disease
- Presents in infancy
-
Figs 12.4A to C: Angioinvasive aspergillosis. CT chest reveals multiple nodules and consolidation in both lungs, showing perilesional ground glass halo.Figs 12.5A to C: An gioinvasive aspergillosis. Chest radiograph (A) shows multiple ill defined nodules in both lungs (arrow). CT chest (B and C) reveals multiple nodules showing perilesional ground glass halo.
- Lymphadenopathy, hepatic and splenic granuloma formation, antral stricture, duodenal fold thickening, enteric fistulas.
Abnormal Mucociliary Clearance
- Autosomal recessive disorder, defective transmembrane electrolyte transport
- Imaging: Central bronchiectasis, peribronchial thickening, mucus plugging and bronchocele, air trapping, atelectasis
- Abnormal sweat chloride test
- Several scoring system described on high-resolution computed tomography (HRCT) (Bhalla, Santamaria, Broody, Helbich)163Figs 12.7A to D: Cystic fibrosis. Chest radiograph (A) reveals bilateral lung hyperinflation with flattened domes of diaphragm. CT thorax (B to D) reveal patchy areas of air trapping (long arrow), giving rise to mosaic attenuation, segmental atelectasis (arrowhead), peribronchial thickening and multiple acinar nodules (suggesting mucoid impaction in distal airways; short arrow).
ACQUIRED DISORDERS
Imaging findings similar to adults. The type of infection depends on the mechanism of immunodeficiency (vide Table 12.1). Only AIDS is being described in detail innthis chapter.
Acquired Immunodeficiency Disorder (AIDS)
- Include both infectious and non-infectious diseases
- Spectrum of disease varies with severity of illness.
Effect of Severity of Illness
Mildly depressed CD4 counts (between 200 and 500 cells/mm3)
More profoundly depressed CD4 counts (<200 cells/mm3) opportunistic infections
- Pneumocystis jirovecii pneumonia (Figs 12.11 and 12.12)
- Bilateral ground-glass opacity, predominantly in a perihilar distributionFigs 12.9A to D: Tuberculosis in the background of HIV infection in a 5-month-old male child with CD4 count > 200 cells/mm3. CT scout film (A) reveals widened right paratracheal stripe (arrow) and right upper zone consolidation. CT chest (B to D) reveals extensive mediastinal necrotic lymphadenopathy and right upper lobe consolidation.Figs 12.10A to D: Tuberculosis in the background of HIV infection in a 10-year-old female child with CD4 count > 200 cells/mm3. CT scout film (A) reveals widened right paratracheal stripe (arrow) and right lower zone consolidation with extensive cavitation. CT chest (B to D) reveals extensive right middle and lower lobe consolidation with cavitation.166Figs 12.11A to C: Pneumocytis jirovecii pneumonia in a 10-year-old male child with HIV infection and CD4 count less than 200 cell/mm3. Chest radiograph (A) is apparently normal. CT chest (B and C) reveals bilateral perihilar ground glass opacities with few pneumatoceles (arrow).
- Thin-walled cysts, often with an upper lobe location, occur in about 30%
- Pneumothorax
- Pleural effusion and lymphadenopathy are rare
- Cytomegalovirus pneumonia (Fig. 12.13)
- Bilateral ground-glass opacities, areas of consolidation, and small centrilobular nodules
- Mycobacterium avium-intracellulare infection
Figs 12.12A and B: Pneumocystis pneumonia with pneumomediastinum and pulmonary interstitial emphysema (PIE) (arrow) in a case of HIV infection in a 2-year-old male child.
Figs 12.13A to C: CMV pneumonia in a 3-year-old girl with AIDS. Chest radiograph revealed perihilar reticular shadows. CT thorax lung window (B) and HRCT image (C) reveal central perihilar ground glass opacities, small nodules with sparing of the peripheral subpleural area.
Non-infectious complications in AIDS
- Lymphoproliferative diseases
- Lymphocytic interstitial pneumonia (LIP)(Figs 12.14 and 12.15)
- Insidious onset of respiratory distress
- Diffuse, symmetric, peribronchial nodules
- Hilar or mediastinaladenopathy
- Thin-walled cystic spaces
- Lymphoma
- Non-Hodgkin lymphoma is the most common
- Hilar and/or mediastinal adenopathy and pulmonary nodules or masses
- Cardiomyopathy
- Dilated cardiomyopathy
- Cardiomegaly with associated pleural effusion and pulmonary edema
- Smooth muscle tumors
- Leiomyoma and leiomyosarcoma
- Others
- Thymic cysts
- Pulmonary hemorrhage
- Drug-induced disease.
Figs 12.14A to D: LIP in the setting of HIV infection in a 18-month-old male child. Chest radiograph (A) reveals right paratracheal stripe widening (arrow), CT chest (B to D) reveals mediastinal adenopathy, peribronchial nodules in both lungs.
Figs 12.15A to D: LIP in the setting of HIV infection in a 12-year-old male child. Chest radiograph (A) reveals bilateral parahilar reticular shadows. CT chest (B to D) reveals right hilar adenopathy (arrow), peribronchial thickening, ground glass opacities (arrow) and micronodules (arrowhead) in both lungs.
Classification
Thoracic masses in children may be pulmonary or extra-pulmonary. Extra-pulmonary masses include mediastinal, pleural and chest-wall lesions.
- Pulmonary masses:
- Congenital
- Infective
- Neoplastic
- Mediastinal (Chapter 8):
- Anterior
- Middle
- Posterior
- Pleural (Chapter 10)
- Chest wall (Chapter 9).
Pulmonary Masses
Congenital (Chapter 4)
- Congenital cystic adenomatoid malformations
- Sequestration
- Bronchogenic cyst
- Vascular malformations.
Infective (Chapter 5)
Neoplastic
Lung tumors:
- Primary
- Secondary.
Primary Lung Tumors
- Benign tumors
- Rare
- Plasma cell granuloma—inflammatory pseudotumor
- Malignant tumors
Inflammatory Pseudotumor
- Also called plasma cell granuloma is a benign tumor showing proliferation of plasma cells, histiocytes and granulocytes. It may represent a response to infection. Any age, second decade commonest.
- Chest radiograph:Large, well-circumscribed mass.
- CT: Large mass with central necrosis and peripheral enhancement.
- Up to 1/4th show calcification. Adenopathy rare, pleural effusion may be seen.
Commonest malignant tumor—Pleuropulmonary blastoma arising from primitive blastomatous tissues. Hence may arise from lung or pleura. Often occur in pre-existing congenital lesions, e.g. CCAM, sequestration, bronchogenic cysts.
Prognosis—Poor.
Chest Radiograph: Solitary pulmonary nodule/large mass, even opaque hemithorax.
CT: Variable appearance: Cystic with mural nodule, mixed cystic-solid or solid. Pleural effusion may be present. Signs of local invasion may be seen, chest wall invasion uncommon. Metastases are to liver or brain.171
Figs 13.1A to F: Recurrent pleuropulmonary blastoma in a 5-year-old boy. Chest radiograph (A) shows volume loss of left hemithorax, uniform haziness of left hemithorax suggesting upper lobe collapse and a mass in left parahilar location. CECT chest (B and C) reveals a solid mass in left lung upper lobe, with left sided pneumothorax. The tumor recurred 1 year after surgery. Chest radiograph (D) and CECT chest (E and F) done 1 year later showed a large heterogeneous solid mass filling almost entire left hemithorax.
Figs 13.2A and B: Pleuropulmonary blastoma in an infant. Chest radiograph (A) reveals opaque left hemithorax. CECT chest (B) shows a large heterogeneous solid mass filling almost the entire left hemithorax.
Figs 13.3A to D: Primary thoracic rhabdomyosarcoma with pulmonary metastases Chest radiograph (A) shows opaque left hemithorax with contralateral mediastinal shift. CECT chest (B to D) shows large left lung mass causing contralateral mediastinal shift and multiple intrapulmonary metastatic nodules in right lung also.
Commoner than primary tumors. Common primaries: Wilm's tumor, Ewing's sarcoma, germ cell tumors, rhabdomyosarcoma and neuroblastoma. Pulmonary nodules/lymphangitis carcinomatosis.173
Figs 13.4A and B: Pulmonary metastases in hepatoblastoma in a 6-month-old boy. CT chest reveals multiple nodules in right lung upper and lower lobe.
Fig. 13.5: Chest radiograph of a child with rhabdomyosarcoma foot showing multiple pulmonary metastases in the right side.
Chest radiograph/CT:
- Single/multiple pulmonary nodules.
- Cavitating metastases: Osteosarcoma, Wilm's tumor. If peripheral can cause pneumothorax. Calcified metastases: Osteosarcoma.
- Miliary metastases: Thyroid carcinoma.
Lymphoma, Leukemia
Primary pulmonary lymphoma rare, commonly secondary involvement.
Chest radiograph: Mediastinal or hilar lymphadenopathy with pulmonary nodules/consolidation.
CT: Parahilar consolidation contiguous to mediastinal and hilar nodes, multiple pulmonary nodules.
Large Masses of Indeterminate Origin
In large masses the origin may be difficult to ascertain (Figs 13.6 and 13.7). The possibilites of a large thoracic mass include pulmonary mass (for ex- pleuropulmonary blastoma, large metastases), pleural mass, chest wall mass (for ex- Ewing's sarcoma, PNET), or diaphragmatic tumor.174
Figs 13.6A and B: CECT chest of a 6-year male showing a large solid thoracoabdominal mass involving right hemithorax, involving right posterior costophrenic sulcus. The diaphragm is not separately seen (either because of diaphragmatic inversion or involvement). The lesion was a biopsy proven pleuropulmonary blastoma.
Figs 13.7A to C: Large mass in right hemithorax. CECT chest axial images (A and B) and coronal reformatted image (C) reveal a large solid mass in right thoracic cavity causing contralateral mediastinal shift, airway compression and large areas of calcification. A diagnosis of neuroblastoma was made on biopsy. The abdominal scan was normal.
Page numbers followed by f refer to figure
A
Accidental trauma ,
Achondrogenesis
Acinar dysplasia
Actinomyces israellii
Acquired bronchiolitis obliterans
Acquired immunodeficiency disorder
Acquired immunodeficiency syndrome
Actinomyces
Acute interstitial
pneumonia ,
pulmonary edema
Adenoid-cystic carcinoma
Agenesis, pulmonary ,
Air bronchogram in neonate, normal appearance of
Air
crescent sign
trapping
Airspace/lobar pneumonia
Airway
compression
diseases
obstruction
Allergic bronchopulmonary aspergillosis
Alveolar capillary dysplasia
Alveolar growth abnormalities
Alveolar microlithiasis, pulmonary
Alveolar proteinosis, pulmonary ,
Anemia, aplastic
Angioinvasive aspergillosis ,
Aortic arch
Aortic knuckle, non-visualization of
Aplasia, pulmonary ,
Artery
agenesis, pulmonary
anomalies, pulmonary
hypertension, pulmonary , ,
interruption, pulmonary
pulmonary
Aspergillosis
Asphyxiating thoracic dysplasia
Asphyxiating thoracic dystrophy
Aspiration
Asthma
Ataxia telangiectasia
B
Bacterial infection , ,
176Bacterial pneumonia , , ,
cavitatory necrosis in
Barcode sign ,
Benign osseous tumors
Benign tumors
Bilateral central bronchiectasis
Bilateral ground-glass opacities
Bilateral pneumothorax
Black bronchus sign
Bone dysplasias ,
Bronchial asthma
Bronchial atresia ,
Bronchial bud development, disorders of ,
Bronchial compression
Bronchiectasis , ,
Bronchiolitis
Bronchoesophageal fistula, congenital
Bronchogenic
carcinoma
cysts , , , , , , , , ,
Bronchopleural fistula , , ,
Bronchopneumonia ,
Bronchopulmonary
dysplasia , , , ,
vascular malformations
Bronchus intermedius, compression of
Bruton's gammaglobulinemia
C
Campomelic dysplasia
Cartilage-hair hypoplasia
Cavitary necrosis ,
Cavitating metastases
Centrilobular micronodules
Cesarean section
Chediak-Higashi syndrome
Chest infections, recurrent ,
Chest wall , ,
bones, osteomyelitis of
Children's interstitial lung disease
Chronic granulomatous disease ,
Chronic lung disease
Chronic neonatal lung disease
Chronic recurrent multifocal osteomyelitis
Cleft palate , ,
Cleidocranial dysostosis ,
Coarse echotexture
Collagen vascular disorders ,
Collapse, pulmonary
Combined B cell and T- cell disorders ,
Congenital abnormalities
Congenital alveolar dysplasia
Costochondral junction
Cystic adenomatoid malformation ,
congenital , ,
Cystic bronchiectasis ,
Cystic fibrosis , , , ,
Cystic hygroma ,
D
Dermatomyositis
Dermoid cyst, anterior mediastinal
Desquamative interstitial pneumonia ,
Diaphragmatic hernia
congenital , , , , ,
Diaphragmatic palsy
Diaphragmatic tumor
177Diaphragms
Diffuse developmental disorders
Diffuse lung diseases
DiGeorge syndrome , ,
Down's syndrome
Duplication cyst ,
Dysplasia ,
E
Ear infections, recurrent
Echinococcus granulosus
Edema, pulmonary
Ellis-van Creveld syndrome
Emphysema, compensatory
Empyema
thoracis
Enteric foregut cyst
Eosinophilic pneumonia
Ewing sarcoma , ,
Extramedullary hematopoiesis ,
Extrinsic airway compression ,
Extrinsic vascular compression ,
F
Fibrosarcoma
Fibrous dysplasia ,
Follicular bronchiolitis , ,
Follicular bronchitis
Foreign body inhalation ,
Fungal balls
Fungal infection , , ,
G
Ganglioneuroma
Gangrene, pulmonary
Gastroesophageal reflux
Genetic surfactant disorders ,
Genetic surfactant dysfunction
Germ cell tumor , , ,
Granulocyte disorders ,
Granuloma
Ground-glass opacities
H
Haemophilus pneumoniae
Haller index ,
Halo sign
Hamartoma
pulmonary
Harrison's sulcus
Heart
and great vessels
disease, congenital
Hemangiopericytoma
Hemithorax, size of
Hemolytic anemias ,
Hemorrhage, pulmonary , , ,
Hodgkin's disease
Hodgkin's lymphoma
Homocystinuria
Hyaline membrane disease , ,
Hydatid cysts
Hyperplasia
Hypersensitivity pneumonia ,
Hypogammaglobulinemia
congenital
Hypogenetic lung syndrome
Hyponatremia
Hypoplasia, pulmonary , , , , , ,
Hypoproteinemia
Hypoxia 178
I
Idiopathic pulmonary hemosiderosis ,
IgA deficiency ,
Immature germ cell tumor
Immunocompromised host
Infancy
cellular pneumonitis of
chronic lung disease of
chronic pneumonitis of , ,
neuroendocrine cell hyperplasia of ,
Infantile cellular interstitial pneumonia ,
Infantile pulmonary hemosiderosis
Inflammatory pseudotumor
Inflammatory upper airway lesions
Interstitial emphysema, pulmonary , ,
Interstitial glycogenosis, pulmonary ,
Interstitial lung disease , ,
Interstitial pneumonia
Intraluminal
airway obstruction
obstruction
Intrinsic
airway abnormalities
upper airway abnormality
Invasive aspergillosis
J
Jeune syndrome
Juvenile idiopathic arthritis
K
Klebsiella pneumoniae , ,
L
Langerhan's cell histiocytosis , ,
Large intrapulmonary bronchogenic cyst
Leiomyoma
Leiomyosarcoma ,
Leukemia , ,
Leukocyte adhesion deficiency
Lobar
emphysema, congenital , , , ,
pneumonia
Lung
abnormalities, congenital
abscess , ,
agenesis ,
hypoplasia
parenchyma, complete absence of
parenchymal complications
tumors
volume, loss of
Lymph nodes ,
Lymphangiectasia, pulmonary
Lymphangioma , ,
anterior mediastinal
Lymphocytic interstitial pneumonia
Lymphoid interstitial pneumonia
Lymphoma , , , , , , , , ,
Lymphoproliferative diseases
M
Malignant
germ cell tumor
179soft-tissue tumors
tumors
Marfan disease
Masses
anterior mediastinal , ,
pulmonary ,
Mature teratoma, anterior mediastinal
Meandering pulmonary vein
Mechanical ventilation
Meconium aspiration ,
syndrome ,
Mediastinal lymphadenopathy , ,
Mediastinal masses ,
classification of
Meniscus sign
Mesenchymal hamartoma , ,
Metastases, pulmonary
Metastatic
disease ,
mediastinal lymph nodes
Middle mediastinal masses ,
Miliary
metastases
nodules
tuberculosis ,
Mimic pneumothorax
Mitral valve prolapse
Morquio syndrome
Mucociliary clearance, abnormal ,
Mucoepidermoid carcinoma
Mucolipidosis
Mucopolysaccharidosis
Mucus bronchogram
Multicompartmental mediastinal lesion ,
Multiple pulmonary
metastases
nodules
Myasthenia gravis
Mycobacterium avium-intracellulare infection
Mycobacterium tuberculosis
Mycoplasma pneumoniae ,
N
Necrotic lymph nodes
Neonatal
chylothorax
interstitial pneumonia
pneumonia , ,
pneumothorax
respiratory distress ,
Neuroblastoma , , , ,
Neuroenteric cyst , , , ,
Neurogenic tumors ,
Nocardiosis
Nodules, pulmonary
Nonaccidental trauma ,
Non-Hodgkin disease
Non-Hodgkin lymphoma , , ,
Non-resolving pneumonia
Nonspecific interstitial pneumonia
Noonan syndrome ,
Normal thymus
O
Obstructive emphysema
Organic foreign body
Osteochondroma ,
Osteogenesis imperfecta , , ,
Osteopetrosis
Osteosarcoma 180
P
Parasitic infection ,
Paratracheal adenopathy
Paravertebral abscess
Parenchyma
Parenchymal lesions
Partial anomalous pulmoanry venous drainage ,
Partial combined immunodeficiency syndromes
Peak respiratory distress
Pectus
carinatum , , ,
excavatum , ,
Peribronchial mass
Peribronchiolar nodules
Persistent fungal infections
Phagocytic disorders
Plasma cell granuloma
Pleuropulmonary blastoma , , , ,
Pneumatocele , , ,
Pneumocystis jirovecii
pneumonia ,
Pneumocystis pneumonia , ,
Pneumomediastinum , ,
Pneumonia , ,
complications of
cryptogenic organizing
recurrent
Pneumonitis, cellular interstitial
Pneumothorax , , , , , , , ,
Poland syndrome , ,
Positive pressure ventilation
Posterior mediastinal
ganglioneuroma
masses , ,
mature teratoma
neuroblastoma
neurofibrosarcoma
neurogenic tumor
Post-infectious bronchiolitis
Post-intubation tracheal stenosis
Postoperative esophagopleural fistula
Predominantly humoral disorders ,
Predominantly T cell disorders
Primary immunodeficiency
Primary lung tumors
Primary pulmonary lymphoma
Primary tracheomalacia
Progressive
primary disease ,
systemic sclerosis
Proximal pulmonary artery interruption
Pulmonary
airway malformations,
congenital
artery
small calibre of
hypoplasia
Pyknodysostosis
Pyopneumothorax
R
Respiratory
distress syndrome , ,
infection, recurrent
Rhabdomyosarcoma , , ,
Rickets ,
S
Sail sign ,
Sarcoidosis , ,
Scimitar syndrome , ,
Scorbutic rosary
181Scurvy ,
Seashore sign ,
Semi-invasive aspergillosis ,
Septic emboli
Sequestration, pulmonary ,
Severe tachypnea
Short rib dysplasia
Short rib polydactyly syndrome ,
Sinus infections
Sjögren syndrome
Small airway abnormalities ,
Small hyperlucent lung
Smooth muscle tumors
Solitary pulmonary nodule ,
Sonographic air bronchogram
Split pleura sign , ,
Spontaneous pneumothorax
Staphylococcal pneumonia
Staphylococcus aureus , ,
Starry sky appearance
Sternum, anterior protrusion of
Storage disease
Storage disorders
Streptococcus pneumoniae , ,
Subcarinal lymph nodes ,
Subclavian artery
Subglottic hemangioma in neonate
Swyer-James-McLeod syndrome , ,
T
Thanatophoric dysplasia
Thoracic duct, congenital malformations of
Thoracic masses
Thoracic skeleton and soft tissues
Thymic cysts , , ,
Thymic hyperplasia , , ,
Thymolipoma , ,
Thymoma ,
Thymus , ,
Thyroid carcinoma
Total anomalous pulmonary
venous
drainage
return
Tracheal agenesis
Tracheal and bronchial branching, disorders of ,
Tracheal bronchus
Tracheal bud, development of
Tracheal displacement
Tracheal foreign body
Tracheoesophageal fistula ,
Tracheoesophageal septum development and fusion, disorders of ,
Transient tachypnea , ,
Tubercular mediastinal lymphadenopathy
Tubercular tracheal stenosis
Tuberculosis , , , ,
sequelae of
Tumors, Ewing sarcoma family of ,
Turner syndrome
U
Unilateral pulmonary venous atresia
V
Vascular congestion
Vascular malformations
Vascular ring
Vascularity, pulmonary
Vein atresia, pulmonary ,
182Venous anomalies, pulmonary
Ventilation, complications of
Vigorous resuscitation
Viral bronchiolitis ,
Viral infection
Viral pneumonia ,
Vitamin K deficiency
W
Wegener's granulomatosis ,
Wet-lung syndrome
Wilm's tumor
Wilson-Mikity syndrome ,
Wiskott-Aldrich syndrome ,
X
X-linked agammaglobulinemia ,
X-linked lymphoproliferative disease