Clinico Radiological Series: Sinonasal Imaging Ashu Seith Bhalla, Manisha Jana, Suresh C Sharma, Smita Manchanda
INDEX
Page numbers followed by f refer to figure fc refer to flowchart, and t refer to table.
A
Accidental trauma 242
Acquired immunodeficiency syndrome 302
Adenocarcinoma 148, 192, 201, 207, 209, 362, 409, 410f
intestinal 145, 145f
non-intestinal type 145
Adenoid 296
cystic carcinoma 142, 143f, 192, 193f, 194f, 207, 210, 354, 354f, 362, 409
hypertrophy 361
chronic 276, 296
Advanced trauma life support 249
AFRS See Allergic fungal rhinosinusitis
AFS See Allergic fungal sinusitis
Agger nasi 44
cell 20, 21f, 42, 52, 70
AIFRS See Acute invasive fungal rhinosinusitis
Air cell 361
Allergic aspergillus sinusitis 308f
Allergic bronchopulmonary aspergillosis 101, 307
Allergic fungal
rhinosinusitis 113115, 115f, 116
sinusitis 79, 100, 100f, 102f, 108, 108t, 109f, 139, 297, 393, 393f, 399, 399f, 413f
Allergic inflammatory sinusitis 141f
Allergic rhinitis 237
Allergic rhinosinusitis 94, 95
diagnosis 94
prevalence of 94
treatment 95
Allergic sinusitis 140
gross pathology 140
histopathology 140
Allergy 363
testing 94
Ameloblastoma 150, 338, 339f, 340f, 401f, 403, 412f
American Academy of Otolaryngology-Head and Neck Surgery 3
American College of Radiology 4
American Joint Committee on Cancer Staging System 202
Amino acid metabolism 100
Amyloidosis 309
Aneurysmal bone cyst 150, 156, 156f, 170, 171f, 286
histopathology 156
Angiography 390
Angioinvasive fungal sinusitis 106
Angioma 363
Angiomatous polyp 411f
Anosmia 183
Anterior skull base 36
arachnoid cyst 93
fractures 317
lesions 316
meningioma 93
Antibiotics 96
Antihistaminics 95
Antral lavage examination 73
Apert's syndrome 332, 333
Aplasias 264
Aplastic anomalies 293
Arch 235
Arhinia 293
Arteriovenous malformation 386f, 387
high flow 386f
Aspergillosis 106, 111f, 363
Aspergillus 99, 110, 116, 139, 140
flavus 107
fumigatus 103, 107, 307
sinusitis 307
Aspirin 384
Asthma 308
ATLS See Advanced trauma life support
Atresia 266
Atretic anomalies 294
Atrophic rhinitis 71, 73f, 370f
Atypical retention cyst 362
Autosomal recessive
disorder 306
inheritance 306
AVMS See Arteriovenous malformations
B
Bacteria, gram-negative 310
Bacterial infection
chronic 296
secondary 95
Bacterial rhinosinusitis, chronic 296
Barotrauma 60
Basal cavity 16
Basal cell carcinoma 200f, 379f
Basal encephaloceles 319
characteristics of 291t
Basal lamella 15, 48
Beam radiotherapy, external 212
Behcet disease 309
Benzodiazepines 362
Bicoronal incision 251
Biopsy 258
Bisphosphonate 186, 345
Black turbinate sign 106
Bone 235
benign tumors of 168
destruction 398f
erosion 72, 122
lesions based on 397fc
expansion 122
marrow transplant recipients 307
sclerosis 122, 396f
tumors of 160, 198
windows 8
Bowel disease, inflammatory 308
Brachytherapy 212
Brain
herniation 245f
parenchyma 122, 245f
Broad aseptate fungal hyphae 139f
Bronchiectasis, extensive 307f
Brown tumors 168
Bulla ethmoidalis 21f, 35f, 44, 48, 52
Burkitt's lymphoma 197
C
Caldwell-Luc procedures 186
Candida 140
Canine fossa 76
Canthal tendon, medial 231t
Canthus masses, medial 284
Carcinoma 137, 138, 143
alveolus infiltrating maxillary sinus 189f
in situ 203
palate eroding into maxillary sinus 344f
Carotid artery
external 383, 390
internal 122, 383, 414
systems
external 383f
internal 383f
Carotid canal 46
Cartilage
benign tumors of 168
tumors of 160, 198
Cartilaginous sinonasal tumors, pathology of 150
Catarrhal stage 311
Cavernous hemangioma 142
Cavernous sinus 101
thrombosis 271
Cells
frontoethmoidal 20
inflammatory 142f
layer, epithelial 142f
lymphomas 146
Cellular stroma 142f, 143f
Cellulitis 61f
Cemento-ossifying fibroma 152
Cephalocele 91, 403
classification, anterior 319
Cerebellar tonsils, low-lying 246
Cerebral abscess 61f, 62, 231
Cerebrospinal fluid 236, 245f, 319, 321, 366, 412
leak 118, 236, 238, 246
rhinorrhea 4, 129, 231, 231f, 247fc, 249, 251
causes of 242, 251
investigations 252
management 252
signs 252
symptoms 252
traumatic 243f, 244f
Cervical lymphadenopathy 196
CGCGs See Central giant cell granulomas
Chemoradiotherapy, concurrent 211
Chemotherapy 202, 209, 213
Chloroma 198, 286
Choanal atresia 259, 266, 295
Choanal polyps 80
types of 82t
Cholesterol crystals 85
Cholesterol granuloma 85
Chondroblastoma 150
Chondroma 150
Chondromyxoid fibroma 150
Chondrosarcoma 150, 157, 157f, 158, 189, 199, 200f, 369, 403f, 405f, 409, 410f
histological features 157
primary 199
secondary 199
Chordoma 150, 362, 369
Churg-Strauss syndrome 306, 309
CIFS See Chronic invasive fungal sinusitis
Ciliary dyskinesia, primary 295, 306, 307f
Clopidogrel 384
Cocaine abuse 72
COF See Cemento-ossifying fibroma
Computed tomography 59, 228
axial image 267f
cisternography 238
techniques 8t
Concha bullosa 11f, 17f, 70, 361
Conchal sphenoid sinus 37
Cone-beam computed tomography 11f
advantages of 11t
disadvantages of 11t
Contrast enhanced
computed tomography 202, 273f, 409
magnetic resonance imaging 65, 202, 409
Contrast magnetic resonance cisternography 240, 241f
Coronal computed tomography image 307f, 308f
Coronal contrast enhanced computed tomography 269f
Coronal soft tissue window 8
Cosmetic recontouring surgery 186
Cranial nerve palsy 271
Craniofacial clefts 294
Craniofacial resection 206
Craniopharyngeal wall, lateral 37
Cribriform plate 44, 235, 242, 321
anatomy 122
defects of 366
disruption 231
superior 15f
Crista galli 32f, 34f, 44, 48, 366
Crouzon's syndrome 92f, 332, 333
Cryptococcus 140
CSB See Central skull base
CSF See Cerebrospinal fluid
Cushing's syndrome 207
Cyst
dentigerous 336f, 401f, 403, 403
dermoid 261, 270f, 291, 292, 316, 321, 321t, 362, 403
epidermoid 261, 284, 316, 362, 403
glial-lined 319
Cystic lesion
hypodense 379f
mixed solid 340f
D
Dacryocystitis 231, 268f, 284
Dacryocystocele 270f, 284
congenital 268, 270t
infected bilateral 269f
Dental
caries 333
etiology 332
infection 73, 333, 334f
lesions, imaging of 332
Dermoid cyst, intranasal 278
Diabetes mellitus 387
Diagnostic provocative tests 94
Diethylenetriaminepentaacetic acid 241
Diffusion weighted imaging 12, 192
Digital subtraction angiography 130
Diplopia 202
DNS See Deviated nasal septum
Drainage pathways, obstruction of 66
DSA See Digital subtraction angiography
Duct, frontonasal 235
Dutcher body 159
Dysphagia 213
E
ECA See External carotid artery
Empty nose syndrome 132
Encephalocele 284, 291, 292, 321, 321t
congenital frontoethmoidal 245f
intranasal 280
Endophthalmitis 351
Endoscopic sinus surgery 118, 127, 130t, 185
imaging, pre-functional 118, 119
post-functional 107f, 118, 126127t
Enophthalmos 231
Epidural abscess 231
Epiphora 231
Epistaxis 390f, 391f
anterior 388
causes of 384t
epidemiology 382
etiology 384
hypertensive 389f
idiopathic 387f
investigations 385
management 387
posterior 388
prevention 391
recurrent 86
relevant anatomy 382
Epithelial tumors, benign 161, 172
Epstein-Barr virus 143
ESS See Endoscopic sinus surgery
Esthesioneuroblastoma 362, 369, 366f, 402f
Ethmoid
bony margins, left posterior 79f
cells, posterior 35f, 36
roof of 238f
sinuses
malignancy 204t
right 351f
skull base height, posterior 35f
trabeculae
deossification of 70f
sclerosis of 66f
thinning of 79f
Ethmoidal air cell, anterior 21f, 23
Ethmoidal artery
anterior 231
canal, anterior 31f
posterior 231
Ethmoidal bulla, enlarged 70
Ethmoidal cells
anterior 21f, 24f, 25f
frontal 70
infraorbital 122
posterior 35f, 36f, 46, 50
supaorbital 124
Ethmoidal sinuses, anterior 18
Ethmoidectomy
anterior 119
posterior 119
procedures, external 186
Ewing sarcoma 189, 195, 286
Expansile cystic lesion, unilocular 336f
Expansile mass lesion 342, 371f
Expansile polypoidal soft tissue bilateral ethmoids 79
Eye
congestion of 213
proptosis, right 115f
Eyebrow, loss of 213
Eyelash, loss of 213
F
Face fractures
middle third 251
upper-third 251
Facial
artery, left 387f
deformity 186
fractures 251, 356t
complex 231t
complications of 232t
hair loss 213
injuries, complex 221
pain 202
swelling 202
trauma 249
FD See Fibrous dysplasia
FESS See Functional endoscopic sinus surgery
Fibroma 364
Fibrosis, cystic 271, 295, 306, 362
Fibrous capsule, development of 85
Fibrous dysplasia 93, 150, 155, 155f, 176, 177f, 179, 179t, 180f, 186, 286, 288, 289, 343, 343f, 364, 400f, 413f
histologic features 155
management of 186
Fibrovascular stroma 152
FLAIR See Fluid-attenuated inversion recovery
Fluid-attenuated inversion recovery 351fc
Foley catheters 389
Foramen rotundum 46
Fossa, infratemporal 106f, 191f
Fovea ethmoidalis 33, 34f, 235, 238f
Fracture
anterior skull base 242f
comminuted 225
complex 225
fragment 232f
frontobasal 322, 322f
Frontal sinus 18, 18f, 42, 44, 48, 121, 185, 235, 242, 261, 402f, 403, 412, 413f
drainage pathway 19, 20f, 21, 21f, 44
fracture 227, 227f, 232
hypoplastic 260f
ostium 19
posterior wall fracture, left 227f
Frontobasal fractures, classification of 322
Frontoethmoidal air cells, types of 22f
Frontoethmoidectomy 184
FSDP See Frontal sinus drainage pathway
Functional endoscopic sinus surgery 16, 97, 118, 119, 132t, 296
basic principles 119
complications of 129
early complications 129
immediate complications 129
indications 119
late complications 132
orbital complications 129
rare complications 132
steps of surgery 119
Fundus 183
Fungal ball 102, 114
Fungal diseases 113
classification 113
diagnosis 116
treatment 116
Fungal infection 79f, 362
invasive 302
superadded 79
Fungal rhinosinusitis 375f
invasive 114, 412
Fungal sinusitis 74, 99, 111, 140, 351, 396f, 404f, 405f
acute invasive 104, 104f, 105f, 116f
chronic invasive 107, 107t, 108, 108t, 109f, 306f, 394f
chronic nongranulomatous invasive 111, 111f
classification of 99
complicated 106f
imaging modalities 100
invasive 4, 99, 104, 107f, 115, 117, 139, 351, 351f, 398f
noninvasive 99, 100
symptoms 104
types 100
Fungiform papilloma 162
Fungus balls 113
Furstenberg sign 320
G
Gastroesophageal reflux disease 272, 295
GC See Gigantiform cementoma
GCRG See Giant cell reparative granuloma
GCT See Giant cell tumors
GERD See Gastroesophageal reflux disease
Germ cell tumor 160, 286
Giant cell 156f
granuloma 341
central 150, 151, 151f, 158
lesions 168
reparative granuloma 168, 170f, 341, 342f, 394f
tumor 168, 169, 170f
Gigantiform cementoma 152
Gillies incision 251
Glands, admixture of 142f
Glioceles 319
Glioma 291, 292, 362
intranasal 280
Globe injury 231
Glomangiopericytoma 146f, 164, 165f
Glucocorticosteroids, topical 95
GnRH See Gonadotropin-releasing hormone
Gorlin-Goltz syndrome 338, 338f
Gossypiboma 130, 132
GPA See Granulomatosis with polyangiitis
Granulomas 363
Granulomatosis 140, 141, 302, 305, 313, 362, 377, 396f, 398f
Granulomatous disease 309, 311, 363
Granulomatous disorders 79, 309, 311
Granulomatous invasive fungal sinusitis, chronic 107, 110f
Grunwald, interlamellar cell of 70
Guitar-Pick sign 351
H
Haemophilus influenzae 95, 139
Haller cell 25f, 70f, 122
Halo sign 252
Hamartoma 273, 362
Hard palate 46, 50
Head and neck tumours, classification of 137
Headache 183, 186
Hemangioma 142, 165, 282, 362, 408f
aggressive 286
capillary 142, 273f
intraosseous 166
sphenoid sinus 166f
Hemangiopericytoma 326, 329
Hematolymphoid 138
neoplasms 196
tumors 146, 160, 189
Hematoma 86
Heminasal aplasia 292f, 293
Hemoglobinopathy 345
Hemophilia 384
A 175
B 175
Hemorrhage, intraorbital 130
High-resolution computed tomography, normal 238f
Holman-Miller sign 174
HPV See Human papilloma virus
Human papilloma virus 137, 148
Hyperostosis 120
Hyperparathyroidism 189
Hyperplasias 264
Hypersinus 91
Hypertension, intracranial idiopathic 246f
Hypertrophy 276, 306
Hypoplasia 74, 75f, 76t, 264
Hyposmia 183
I
ICA See Internal carotid artery
Idiopathic intracranial hypertension, radiological signs of 246t
IFS See Invasive fungal sinusitis
IMA See Internal maxillary artery
Immunodeficiency, severe combined 302
Immunotherapy 95
Inappropriate antidiuretic hormone secretion, syndrome of 207
Infantile frontonasal capillary hemangioma 272
Infection 302, 348
intracranial 231
severe 349
Infectious rhinosinusitis, recurrent acute 95
Inflammatory disorders 348, 352
chronic 303
gamut of 301
Influenza 139
Injuries, intracranial 130
Intracranial tumors, primary 329t
Intrasinus synechiae 271
Ipsilateral metastatic lymph node
multiple 204
single 204
Itraconazole 117
J
JPOF See Juvenile psammomatoid ossifying fibroma
JTOF See Juvenile trabecular ossifying fibroma
Juvenile nasopharyngeal angiofibroma 173, 173fc, 174f, 175f, 186, 263, 354f, 362, 372f, 373, 381, 385f, 390f, 391f, 396f, 405f, 408f, 410f
extension of 414f
Juvenile ossifying fibroma 401f, 407f, 153
Juvenile psammomatoid ossifying fibroma 152, 154, 154f
Juvenile trabecular ossifying fibroma 152
K
Kallmann syndrome 321
Keratocystic odontogenic tumor 336, 337f, 394f, 401f, 403, 412f
multiple 338f
Keros classification 31
Kiesselbach's plexus 384
Klebsiella ozaenae 72
Klebsiella rhinoscleromatis 310
KOT See Keratocystic odontogenic tumor
L
Lacrimal drainage system, disruption of 130
Lacrimal duct injury 231
Lacrimal sac injury 231
Lamella
lateral 44, 46
medial 44, 46
Lamina papyracea 15, 16f, 25f, 27, 30f, 35, 44, 46, 122, 129, 235
bulging of 79f
Large B-cell lymphoma, diffuse 197f, 398f
Le Fort fractures 221, 223f
types of 222f, 222t
Leprosy 140, 302, 303f
Lesions
benign 398, 399t, 410f
congenital 332
cystic 400, 402f, 403t
density of 399
fibro-osseous 176, 179, 341
inflammatory 139
malignant 399t, 410f
Leukemia
acute 198
myelocytic 276f
clinical background of 198f
Ligation techniques 390
Lipoblastoma 273
Lipodermoid 284
Lipogranuloma 132
Lobular capillary hemangioma 142
Lund-Mackay system, modified 65
Lupus vulgaris 363
Lymph node
contralateral metastatic 204
involvement 211
regional 204
Lymphatic spread pathway 210, 210t
Lymphoepithelial carcinoma 143
Lymphoid tissue, mucosa-associated 158
Lymphoma 189, 196, 197f, 286, 362, 398f, 404f
B-cell type 196
Lymphovascular invasion 211
Lynch incision 184, 185f
M
Macroadenomas 326
Magnetic resonance
cisternography 239
imaging 59, 192, 321, 337f
of paranasal sinuses 12f
planning 12t
Mandible, irregular lytic-sclerotic destruction of 214f
Mapping sinus involvement 120
Markowitz and Manson classification 225
Masses 335
benign 286
congenital 277fc
differential diagnosis of 284
frontonasal 282
lesion, heterogeneous 191f, 193f, 195f
malignant 286
with intense enhancement 408f
with mild-moderate enhancement 407f
Maxilla
frontonasal process of 19
osteonecrosis of 344, 345f, 346f
Maxillary alveolus, bony scalloping of 379f
Maxillary antrum
infrastructure of 210
suprastructure of 210
Maxillary artery, internal 390
Maxillary bone 39, 195f
Maxillary buttress
lateral 220, 221f
medial 220, 221f
posterior 220, 221f
Maxillary cancer 209
Maxillary dentition, abnormal 266
Maxillary fracture, posterior 229f, 232
Maxillary mucosal disease, right 61f
Maxillary nonseminomatous germ cell tumor 401f
Maxillary ostium 21f, 27f, 30f, 44, 46, 371f
abnormal 30f
plane of 30f
Maxillary sinus 15, 25, 42, 63, 68f, 80f, 121, 174, 185, 201, 212, 235, 261, 304, 332, 401f, 403, 410
anatomy of 24
bilateral 12f, 64f, 260f
cancers 209
carcinoma 190f
diseases, bilateral 346
fractures 229, 229f
granulocytic sarcoma, left 276f
hypoplastic 70
left 26f
malignancy 202, 203t, 204t
medial wall of 16f
mucosa 203
mucosal thickening, hyperintense bilateral 13f
opacified left 68f
ostium 69
parts of 42
right 371f
roof fractures 232
roof of 35f
small 75f
superior wall of 26f
Maxillary sinusitis 333, 334f
bilateral 104f
chronic left 74f
Maxillectomy 186
infrastructural 206
medial 184, 205, 205f
posterior 206
total 184, 206, 206f
Maxillofacial trauma 219
Meatal antrostomy, middle 119
Meatus
inferior 44, 46
middle 44, 46
Medial rectus muscle entrapment 230f
Melanoma 195, 404f
malignant 362
Meningioma 329, 362, 410f
Meningitis 61f, 231
Meningoceles 246
Meningoencephalocele 290
frontonasal 402f
Mesenchymal cells 151f
Mesenchymal tumors 362
Messerklinger technique 119
Metastasis 199, 286, 328, 362
Metastatic lymph node 204
bilateral 204
Metastatic lymphadenopathy, low incidence of 192
Methyl green-pyronin 159
Midface
anomalies 261
hypoplasia 92f
Midnasal stenosis 294
Mikulicz cells 311
Moraxella catarrhalis 139
Mouth, dryness of 213
MRI See Magnetic resonance imaging
Mucocele 77, 87, 91f, 126, 186, 286, 394f, 402f, 403, 413f, 414f
causes of 90
ethmoidal 90f
frontal 88f, 89f, 407f
secondary 91f
Mucociliary deficiency 271
Mucormycosis 104f, 106, 107f, 303f, 363
Mucosal atrophy 73f
Mucosal disease 349f
Mucosal lesions 344
Mucosal thickening 64
inflammatory 90
Mucositis, esophageal 213
Mucous form 85
Multidetector computed tomography 120t, 219, 265
Muscle injury, extraocular 130
Muscle, extraocular 351
Mycetoma 102, 103f, 113, 114, 116, 394f, 399, 399f, 407f, 411, 411f
Myeloma, multiple 197
Myeloproliferative disorders, spectrum of 198
Myoepithelial cell layer 142f
Myofibroblastic tumor, inflammatory 164, 165f
N
Nasal bone 42, 238f, 235
comminuted fracture
bilateral 228f
right 228f
fracture 227, 232
left 228f
hemangioma 167f
hypoplastic 264f
Nasal cavity 14, 57, 79f, 80f, 191f, 209, 210, 235, 274f, 311, 369, 373t
anatomy of 15
anomalies 265
anterior 387f
boundaries 15f
lateral wall of 16f
lesions 370f
causing obstruction 371f
masses 278, 280, 372f
right 371f
superior 366f
tumors of 209
vascular polyp of 312f
walls of 259
Nasal conditions, inflammatory 55
Nasal cycle, physiological 361
Nasal decongestants 363
topical 95
Nasal dermal sinus 261, 316
tract 278
Nasal dermoid 292f
Nasal discharge 182
causes of 237
Nasal duct pathway, frontal 122
Nasal encephalocele 261
Nasal endoscopy 96
Nasal glioma 261, 280, 317
Nasal hair loss 213
Nasal lesions
common erosive 377fc
external 378f
Nasal melanoma 213f
Nasal mucosal atrophy 306
Nasal obstruction 182, 201, 361
causes of 362t
clinical
examination 363
presentation 361
diagnostic imaging 364
Nasal packs 388
anterior 389
posterior 389
Nasal polyps 77
etiology 77
imaging 78
pathology 78
Nasal pyriform aperture stenosis 294
congenital 265, 265f
Nasal septal
destruction 376f
deviation 17f
lesions 374, 374t
perforation 131f
without mass lesions 375f
Nasal septum 16, 42, 44, 46, 122, 130, 185, 304, 365
blood supply of 383f
destruction of 309f, 311
deviated 70, 122
injury 227, 313
parts 16f
Nasal sinus 318f
Nasal turbinates 17, 191f
destruction of 197f
Nasal vestibule 210, 212
left 379f
lesions of 379f
Nasal wall
lateral 185
lesions, lateral 373t
Nasoalveolar cyst 379f
Nasobuccal membrane, developmental errors of 295
Nasociliary groove 228f
Nasoethmoidal cephalocele 319
Nasoethmoidal encephalocele 320f
Nasoethmoidal lesions 365
Nasoethmoidal masses 368f, 369t
of bony origin 367f
Nasoethmoidal polyposis 79f
Nasofrontal cephalocele 319
Nasofrontal encephalocele 319f
Nasofrontal suture 220
Nasolacrimal apparatus anomalies 268
Nasolacrimal duct 42, 48, 50, 259, 263, 270, 311, 354, 354f, 362
bilateral cystic dilatation of 269f
block 72
dilatation 269
inflammation 350f
melanoma 355f
stenosis 268, 268f
Nasomaxillary suture 228f
Naso-orbital encephalocele 319
Naso-orbitoethmoid complex fractures 225, 225f, 231
Naso-orbitoethmoid fracture 221, 225f, 226f, 228f
Nasopharyngeal
angiofibroma 138, 142, 143f
carcinoma 191f, 373
mucosal inflammation 306
soft tissue, posterior 277f
tumors, benign 173
Nasopharynx 122, 364
angiofibroma 364
carcinoma 364
Natural killer T-cell lymphoma 147f, 197f, 309f
NB See Neuroblastoma
NEC See Neuroendocrine carcinoma
Neck
dissection 203
nodes, regional 204t
swelling 202
Necrosis, avascular 304
Neo-osteogenesis 396f
Neoplastic lesions
benign 141
malignant 143
Neovascularization, subsequent 85
Nerve
canal, infraorbital 25, 76
entrapment, infraorbital 230f
sheath tumor, nasal benign 274f, 282
Neuroblastoma 148, 286
Neuroectodermal malignancies 195
Neuroectodermal tumor 160
malignant 147
Neuroendocrine carcinoma 148
Neurofibroma 167, 169f, 371f
Neurofibromatosis 167
Neuropore errors, types of anterior 292t
Neutrophils 145f
Nodular mucosal thickening 304
Nonallergic rhinitis 363
Noncontrast computed tomography 59, 80, 80f, 275f, 346
Nonenhancing masses 407f
Nongranulomatous disease 107t
Non-Hodgkin's lymphoma 146, 147f, 398f
Non-intestinal adenocarcinoma 146f
Non-keratinizing squamous cell carcinoma 143, 144f
Non-neoplastic
lesions 137, 139
sinonasal lesions 138t
Nonodontogenic lesions 333, 341
Nonpneumatized frontal sinus 19f
Nonpneumatized sphenoid sinus 37
Nonsteroidal anti-inflammatory drugs 308, 387
Nontraumatic cerebrospinal fluid 317
rhinorrhea 324
Nose 113, 204t, 363
benign tumors of 160, 363
causing epistaxis 386f
congenital malformations of 290
external 378, 380t
lesions, external 380
NSAIDs See Nonsteroidal anti-inflammatory drugs
O
Obstructive right maxillary sinusitis 90f
Obstructive sinusitis 186
OCS See Orbital compartment syndrome
Odontogenic cysts 335
Odontogenic lesions 333
large 407f
Odontogenic myxoma 340, 341f
Olfactory bulb 32f
Olfactory fossa 44, 46
anatomy of 31
bilateral deep 128f
boundaries 32f
types of 33f
Olfactory nerve injury 324
Olfactory neuroblastoma 147, 147f, 207
Olfactory neuroepithelium, basal cell of 207
Olfactory schwannoma 328f
OMU See Osteomeatal unit
Oncocytic papilloma 163
Onodi cells 36, 36f, 122, 124
Opaque maxillary sinus, small 71f
Opaque sinus 75f, 76
Ophthalmic injuries 130
Optic canal 46, 235
Optic nerve 355
anatomy 122
canal 38f
injury 130, 231
Optic neuritis, infectious 271
Oral azole antifungals 117
Orbit 235, 348t
boundaries of 39f
enlargement of 71f, 75f
granulocytic sarcoma of 198f
ipsilateral 195f
Orbital abscess 349
Orbital apex 46
syndrome 231
Orbital blowout fracture 229, 232
right inferior 230f
Orbital cellulitis, right 350f
Orbital compartment syndrome 349
Orbital complication 60, 129
evolution of 350, 350fc
Orbital extension 311
Orbital fissure
inferior 61f, 235, 354, 354f
syndrome 231, 235
widening of inferior 168
Orbital nerve
canal, inferior 26f, 44
inferior 44
Orbital penetration, risk of 25
Orbital plane, mid 34f
Orbital pseudotumor 352
Orbital wall blowout fracture, left inferior 230f
Oroantral fistula 74f
post-tooth extraction 334f
Oronasal fistula 333
Orthopantogram 335, 339
Ossifying fibroma 91f, 150, 152, 153f, 177, 179, 179t, 180f, 186, 286, 288, 289, 342, 343f, 364, 407, 413
Osteitis 79f
Osteoblastoma 150, 171
Osteochondroma 150
Osteoclastic multinucleated giant cells 151f
Osteoid osteoma 150
Osteoma 150, 152, 152f, 171, 286, 362, 364, 400f, 413f
frontoethmoidal 172f
Osteomeatal complex 27f, 78f, 119
widening of 79f
Osteomeatal unit 127
anatomy of 26
components of 44
pattern 68f
widening of 64f, 70f
Osteomyelitis 271, 394, 396, 396f
Osteonecrosis 189
Osteoradionecrosis 213, 214f, 396f
Osteosarcoma 150, 189, 199
Ostium block 411f
Otolaryngological procedures 244
Otolaryngology 96
Otorrhea 236
P
Pain, severe 186
Palatine bone 39
Palliative radiotherapy 211
Pamidronate 186
Panoramic radiography 346
Papilloma 362, 363
antrochoanal 82t
inverted 82t, 142f, 161, 162f, 185, 363, 371f, 373, 405f, 408f, 411f
recurrent inverted 163f
squamous 363
Paradoxical middle turbinate 70
Parainfluenza viruses 139
Paranasal sinuses 3, 5t, 7f, 15, 113, 146, 160, 191f, 201, 307f, 364
computed tomography of 8
development of 259
maturation of 260t
radiograph of 6f, 7f
radiographic development of 259f, 260f
tumors of 209
Parathormone 168
Pediatric chronic sinusitis 271
Pediatric sinonasal
disorders 257
classification of 261, 262t
congenital 261
inflammatory 270
masses 263fc
Perineural invasion 211
Periodic acid-Schiff stains 139f
Periodonitis 333
Periorbital lipogranuloma 130
Periostitis 61f
Peripheral hypodensity 102f
Peripheral nerve sheath tumors 167
Persistent sinonasal disease 332
Pharynx 57
Pituitary macroadenoma 92f, 326, 329
extension of 414f
Plain magnetic resonance cisternography, normal 241f
Planum sphenoidale 321
meningioma 325f
Plasma cell
mature 158
neoplasm 189, 197
Plasmacytoma 150, 158, 158f
differential diagnosis 159
histopathology 158
of nasal bone 158f
Pleomorphic adenoma 141, 142f, 163, 164f, 362, 405f
PNET See Primitive neuroectodermal tumor
Pneumatized basal lamella 124
Pneumocele 92
Pneumocephalus 244f
Pneumosinus 91
dilatans 91, 92f
Polyangiitis 140, 141, 302, 303, 305, 313, 362, 377, 396f, 398f
Polyarteritis nodosa 306
Polychondritis 305
Polycyclic hydrocarbons 201
Polyp
antrochoanal 82, 286, 297, 394f, 408f, 411, 411f
basis of imaging appearance of 81t
ethmoidochoanal 83f, 84
Polypoid mucosal disease 64f
Polypoidal mass 81f, 83f
Polypoidal soft tissue 313
Polyposis 79f, 97, 286, 370f
diagnosis 97
treatment 97
Polyps 77
inflammatory 405f
Polyrhinia 264
Positron emission tomography 4, 192
Postcontrast slight enhancement 269
Postembolization angiogram 387f
Posterolateral wall 235
Posteromedial wall 235
Post-FESS
appearance 128f
complications 131f
contralateral disease 129f
polyp recurrence 128f
Postviral infection 345
Pott's puffy tumor 62, 271, 412
Premaxillary soft tissue, left 104f
Primitive neuroectodermal tumor 195, 196f, 353f, 376
Proboscis lateralis 264, 264f, 294
Proptosis 202
Psammomatoid bodies 154
Pseudoaneurysm 130
Pseudotumor 352f
hemophilic 175, 176f, 275, 275f
inflammatory 165f
Pterygoid plate 46, 220, 224f, 229f, 235
medial 46
Pterygoid tubercle 229f
Pterygomaxillary fissure 385f
widening of 385f
Pterygopalatine fossa 235, 385f
Purulent nasal discharge 363
Pyogenic granuloma 142
Pyomyositis 271
Pyriform aperture 259
R
Radiation 209, 213
dermatitis 213
dose, lower 11
Radioallergosorbent test 94
Radiofrequency ablation 127
Radionuclide cisternography 241
Radiotherapy 202, 211
adjuvant 211
intensity-modulated 212
management, site-specific 212t
treatment, modes of 212t
Radkowski staging 186, 187t
Rectus muscle, inferior 356f
Red nasal mucosa 363
Respiratory
disease, aspirin-exacerbated 308
tract infection, recurrent upper 271
Restricted diffusion 410f
Retention cyst 84, 85f, 395f, 401f, 402f, 403
RFA See Radiofrequency ablation
Rhabdomyosarcoma 189, 198, 263, 286
Rhinitis 306, 362
medicamentosa 362
Rhinolith 364, 373
Rhino-orbito-cerebral mucormycosis 101f
Rhinorrhea 130, 236, 246f, 317
Rhinoscleroma 138, 309, 310, 373, 411
Rhinosinusitis 57, 138, 270, 295, 362, 363, 373
acute 296
infectious 95
invasive 116
bacterial 296, 412
chronic 62, 65, 66f, 67t, 78, 94, 95, 97, 98t, 370f, 393, 393f, 394f, 396f, 411f
infectious 95
invasive 115
forms of 100
infectious 95, 96t
infective 139
treatment, chronic infectious 96
Rhinosporidiosis 138, 139, 140f, 311, 312f, 364, 373
Rhinosporidium 140
seeberi 139, 311
Rhinotomy
incision, lateral 184, 185f
lateral 186
Rhinovirus 139
Rhizopus 116
Root of nose, region of 277fc
Russell bodies 311
S
Salivary gland
tumors 138, 141
type adenomas 163
Samter's triad 308
Sarcoid 363
Sarcoidosis 304
Sarcoma
fibromyxoid 409
granulocytic 189, 198
Sarcomatoid 143
SCC See Squamous cell carcinoma
Schwannoma 167, 362
Scleroma, histopathology of 310
Sclerosis 66f, 305f
bony 368f
Sclerotic bone, hypointense 305f
Sellar sphenoid sinus 37
Septal cartilage 232
Septal deviation 16
Septal pneumatization 17
posterior 17f
Septal spurs 17
Septum
bony 26f
cartilaginous 42
fibroangioma of 363
Shock, electric 345
SIADH See Syndrome of inappropriate antidiuretic hormone secretion
Sickle cell anemia 345
Silent sinus syndrome 68, 71f, 75f, 76t
Silver methenamine stains 139f
Silver nitrate 388
Sincipital encephaloceles, characteristics of 291t
Sinonasal
anatomy
section-wise 41
structure-wise 14
angiomatous polyp 85, 87f, 394f, 405f, 408f, 411
cancers 209t
carcinoma 195f
cavity 14, 93, 236, 301, 302, 302fc, 332, 333t, 341, 348t
bilateral 70f
chloroma 275
complications 130
diseases 4
epithelium and cysts 142f
fractures 221
glomangiopericytoma 145
infections, diagnosis of 140t
inflammation, chronic 311
inflammatory pathology 3
injuries, bony 250
lesions
classification of 138
congenital 366
hyperdense 399f
of heterogeneous density 401f
of osseous density 400f
pathology of 137
malignancy 188, 210t, 211, 211t
malignant tumors 148fc
nerve sheath tumors 274
neuroendocrine carcinoma 194
organized hematoma 85
origin, epithelial tumors of 202
papillomas 138, 141, 161
polyposis 60, 66, 70f, 77, 78f, 393
polyps 79, 140
sarcoma, biphenotypic 137, 145
schwannoma 282
tract 137, 196
trauma 219, 249
tuberculosis 73
tumors 160, 189, 207, 214
benign 180, 182
cartilaginous 150t
classification of 150
malignant 201, 202, 209
of epithelial tumors, malignant 202
undifferentiated carcinoma 144
Sinus 195f
angioma of 363
drainage of 25
pathways 70t
drains 15
ethmoid 23, 63f, 92f, 102f, 121, 185, 193f, 196f, 203t, 210, 235, 243f, 244f, 245f, 261, 308f, 309311, 402f, 403
expansion 235
floor 235
hypoplasia 25
large air filled 91, 92f
lesions 392
laterality 393
masses 286, 288
normal size 395f
opacification of 63f, 65, 235
parts of frontal 42
pneumatization of 121
septae 235
cell, interfrontal 22f, 70
sets of 15
size of 394
walls, status of 120
window 8, 102f
Sinusitis 12f, 13f, 73, 306, 408f, 416t
acute 59, 60, 62t, 271, 395
bacterial 396f
chronic 4, 58f, 60, 72, 271, 395f, 399, 399f, 413f
complicated acute 59, 348, 398f
complication of 4, 61f
ethmoid 307f
intracranial complications of 61f
orbital complication of 349f
recurrent 4
chronic 140
Sjögren's syndrome 306
Skull base
complications 130
foramina, widening of 246
intact of 239f
lesions
anterior 317t
congenital anterior 316
median anterior 31, 36
Smell function 366
Soft palate 46
Soft tissue
density 80f, 351f
mass 164f
edema 105
injuries of face 250
mass 200f
expansile 78f, 79f
hyperdense 276f
mild 396f
opacification 370f
premaxillary 335f
thickening 303
tumors of 160, 198
benign 138, 165
low malignant potential 164
malignant 138, 145
nasopharynx 138
windows 8
Solitary fibrous tumor 326, 329
Sphenochoanal polyp 84
Sphenoethmoidal recess 37, 37f, 69f, 122
obliteration of 69f
Sphenoethmoidal region 412
disease entities of 414f
Sphenoid 127
bone, small 92f
cells 50
mucocele 89f
mucosal enhancement 61f
ostium 50, 52
sinus 35f37f, 38f, 46, 52, 83f, 107f, 121, 185, 209, 210, 235, 242, 245f, 261, 349f, 402f, 412
anatomy of 36
presellar 37
types of 37f
Sphenoidotomy 127
posterior 119
Sphenopalatine artery 383
Spindle cell 143
Spindle-shaped cells 154
Spontaneous cerebrospinal fluid 246f
rhinorrhea 324
Spontaneous leaks 242, 246
Sprengel's deformity 338
Squamous cell carcinoma 143, 148, 189, 201, 209, 353f, 362, 395f, 396f, 407f, 411, 411f
keratinizing 143, 144f
of maxillary sinus 191f
staging system 202
Stenosis 266
Streptococcus pneumoniae 95, 139
Stroma, edematous 140
Structured reporting format 121t
Subdural empyema 271
Subepithelial large sporangia 140f
Subfrontal schwannoma 327, 329
Subperiosteal abscess 61f, 271, 349f
Supernumerary nostril 264, 294
Supraorbital cells 24f
Surgery 184, 202
Symphysis menti 235
Synechiae 72
Syphilis 363
infection 303
Systemic corticosteroids 95
Systemic disorders 299
chronic 272
classification of 302fc
Systemic lupus erythematosus 302, 306
T
T cells, nuclear factor of activated 151
Teeth, loosening of 202
Tegmen tympani 242
Telecanthus 231
Temporal fossa 193f
Temporal hairline 251
Temporalis muscle 106f
Tennis racket 340
Teratocarcinosarcoma 146
Teratoma 272
mature 172
TESPAL See Transnasal endoscopic sphenopalatine artery ligation
Tetrapod fracture 226f, 231
Trabecular juvenile ossifying fibroma 153
Transnasal endoscopic sphenopalatine artery ligation 390
Transsphenoidal encephalocele 320f
Transverse mandibular buttress, lower 220, 220f
Transverse maxillary buttress, lower 220, 220f
Transverse sinuses, stenosis of 246
Trauma 321, 355, 317
complications 324
Treponema pallidum infection 303
Tuberculosis 140, 302, 363
Tumor 91f, 158, 204, 324, 348, 352, 401f
benign 150, 151
cartilaginous 158t
cells 143f, 145f
contiguous perineural extension of 194f
direct extension 352
epithelial 160
evaluation 4
extension, intracranial 190
fibro-osseous 186
head and neck 160
high grade 211
like lesions 150
location 210
malignant 157
meningioma 324
node and metastasis staging 202, 203t, 204t
of nose, malignant 201
of sinonasal cavities, malignant 188
spillage 211
Turbinate, inferior 42, 44, 46
U
Unilateral disease 394f
Unilateral maxillary sinus 411f, 412f
disease 411fc
Unilocular cystic lesions, multiple 337f
Upper transverse
mandibular buttress 220, 220f
maxillary buttress 220, 220f
V
Vascular injury 130
Vascular tumors, benign 165
Vasculitides 140
Vasoconstriction, severe 72
Vertebral anomalies 338
Vessel vasculitides, types of small 141
Vestibular lesions 380, 380t
Vidian canal 46
Vision
field of 183
loss 231
Visual acuity 183
Vital structures, compression of 186
Volume rendering technique 10
Voriconazole 117
W
Wait and watch policy 184
Weber-Ferguson incision 184, 185f
Wegener's granulomatosis 137, 141, 362, 363
Widal's triad 308
Wigand technique 119
World Health Organization classification of sinonasal tumors 138t
Z
Zygoma 224f, 305f
Zygomatic bone 39, 223f, 226, 235
erosion of 61f
Zygomaticofrontal suture 220, 226f
Zygomaticomaxillary
complex fracture 221, 226, 231
suture 226f, 235
Zygomaticotemporal suture 226f
Zygomycosis 139f, 140
×
Chapter Notes

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1Normal Anatomy and Imaging
  1. Imaging Modalities and Techniques
  2. Sinonasal Anatomy: Structure-wise
  3. Sinonasal Anatomy: Section-wise2

Imaging Modalities and TechniquesCHAPTER 1

Devasenathipathy Kandasamy
Chandrashekhara SH
 
INTRODUCTION
  • Paranasal sinuses (PNS) are air-filled structures located around the nasal cavity and formed with in the bones of the skull and face. The various functions are decreasing the weight of head, conditioning the inhaled air with moisture and heat and increasing the resonance of speech.
  • There are four sets of sinuses on either sides namely, maxillary, frontal, ethmoid and sphenoid sinuses.
  • Imaging of sinonasal pathology has evolved over the last three decades and advances in imaging have changed the way we look at diseases.
  • The unprecedented detail in which the PNS and skull base anatomy are visualized in current generation imaging was not possible earlier.
  • Parallel growth of new techniques and approaches, such as endoscopic and image guided surgeries have also increased the demand on imaging.
  • Sinonasal inflammatory pathology is very common and usually secondary to infection or allergy.
  • Most of them do not need imaging evaluation.
  • There specific scenarios where imaging evaluation is indicated.
  • American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) published a consent statement in 2012 aiming to guide the choice of imaging in the evaluation of sinonasal diseases (Table 1.1) .1
The consent statement also published the scenarios where imaging is not indicated:
  • Uncomplicated sinusitis or upper respiratory tract infections.
  • Responding to medical treatment.
  • Children less than 3 years with uncomplicated acute sinusitis.4
Table 1.1   Indications for imaging.
S. No.
Indications
1.
2.
3.
4.
5.
6.
7.
8.
Chronic sinusitis not responding to medical treatment
Recurrent sinusitis
Complication of sinusitis
CSF rhinorrhea
Invasive fungal sinusitis in immunocompromised individuals
Tumor evaluation
Preoperative planning for new or revision surgeries
Complications of surgery
To prevent misuse of imaging modalities American College of Radiology (ACR) has published its ACR appropriateness criteria in 2013, which rates the usefulness of an imaging modality in a given situation.2
 
IMAGING MODALITIES
The imaging modalities which are used to evaluate sinonasal diseases are:
  • Radiographs
  • Computed tomography (CT)
    • Multidetector CT (MDCT)
    • Cone-beam CT (CBCT)
  • Magnetic resonance imaging (MRI)
  • F-18 FDG positron emission tomography (PET).
 
Radiographs
Plain radiographs were used to evaluate PNS before the advent of CT scans.
 
Techniques
  • Standard four view sinus series include (Table 1.2):
    • Water's view (occipitomental) (Fig. 1.1)
    • Caldwell's view (occipitofrontal) (Fig. 1.2)
    • Lateral view (Fig. 1.3)
    • Submentovertical view.
  • The above standard set of views provide good assessment of PNS (Figs. 1.4A to D). Amongst these Water's view is most frequently employed.
  • Abnormalities manifest as opacification of sinuses, bone destruction, soft tissue or displacement of structures.
  • However, the sensitivity and specificity of plain radiographs are poor compared to newer modalities which make it a less favored modality.
  • In a properly exposed radiograph, PNS density is identical to orbital density.
  • Erect or sitting position used during radiography of PNS to identify presence or absence of fluid and to differentiate fluid and thickening caused by other pathology.
  • The recent AAO-HNS guidelines are also not in favor of using plain radiographs for the evaluation of sinusitis.1
  • Currently, the utility of radiographs is very limited.5
Table 1.2   Various radiographic views of paranasal sinuses (PNS).
Projection
Method/name
Technique
PNS visualized
Structures visualized
Lateral
R or L
Head in true lateral position
All paranasal sinuses
Integrity of the posterior antral bony margins
Air-fluid level in the sphenoid sinus
Sella turcica and nasopharynx are well seen
PA axial 15°
(Occipitofrontal)
Caldwell
Radiographic baseline (OM line) is perpendicular to the bucky
CR angled caudal 15°
Frontal and anterior ethmoidal sinuses
Best projection for examining the frontal and ethmoid sinuses in the frontal projection
Occipitomental
Water's
Closed mouth
OM baseline or radiographic baseline 45° from horizontal
CR perpendicular to IR
Maxillary sinuses
Evaluation of maxillary antra, roof of orbit, frontal sinus
Occipitomental
Water's
Open mouth
OM baseline or radiographic baseline 45° from horizontal.
Open mouth
Maxillary and sphenoidal sinuses
Better evaluate lower posterior sphenoid sinus
Submentovertical
Basal view
Infraorbitomeatal line is parallel to the IR and bucky
Ethmoidal and sphenoidal sinuses
Anterior and posterior walls of the frontal sinuses
The lateral and medial walls of the maxillary antrum
(OM line: Orbitomeatal line; CR: Central ray; IR: Image receptor).
6
zoom view
Fig. 1.1: Radiograph of paranasal sinuses (PNS)—Water's view.
zoom view
Fig. 1.2: Radiograph of paranasal sinuses (PNS)—Caldwell's view.
7
zoom view
Fig. 1.3: Radiograph of paranasal sinuses (PNS)—Lateral view.
zoom view
Figs. 1.4A to D: Schematic diagram of various radiographic views of paranasal sinuses (PNS).
8  
  • CT scan is the modality of choice and the workhorse for the evaluation of sinonasal diseases.
  • The ability of CT scan to show the sinuses in much better detail coupled with good spatial resolution has practically replaced plain radiographs.
  • Findings, such as sinus opacification, bone destruction, mucoperiosteal thickening and normal variations in the anatomy are not only valuable in the diagnostic point of view but also for the preoperative planning in these patients.
zoom view
Figs. 1.5A to C: Computed tomography (CT) of paranasal sinuses (PNS). (A) Coronal soft tissue window; (B) Coronal bone window; and (C) Sagittal bone window sections used for PNS evaluation.
Table 1.3   Computed tomography (CT) techniques.
  1. Axial plane: parallel to the infraorbitomeatal plane
  2. Craniocaudal: Frontal sinus to hard palate
  3. Tube current: 120 kVp, tube current modulation with quality reference mAs of 80
  4. 0.6 mm acquisition with reconstruction of data into 1–3 mm sections in axial, coronal and sagittal planes
  5. Bone windows: Width 3500, center 300
  6. Soft tissue windows: Width 270, center 70
  7. Sinus windows: Width 2000, center 4009
 
Multidetector Row Computed Tomography (MDCT)
  • Role of MDCT
    • Axial scanning avoids the extension of head
    • Lack of obscuration of important anatomy by spray artifact from dental restoration
    • Allow more refined reconstructions in other plane than the primary scan plane.
  • Role of Coronal Reconstructions
    • Primary imaging orientation
    • Best shows osteomeatal unit
    • Relationship of ethmoid roof to brain
    • Correlate with surgical orientation.
  • Role of Sagittal Reconstructions
    • Better visualization of frontal recess and frontal sinus, these are areas of persistent and recurrent sinus disease
    • Better show sphenoid sinus and basal lamella and agger nasi cell, contributing the safer and accurate endoscopic procedure.
  • Whenever CT scan images are reviewed, it is best to visualize all three planes simultaneously and they must be linked. So that when the cursor is kept on any plane the other two planes will align accordingly to the same point of interest (Figs. 1.6A to D).
zoom view
Figs. 1.6A to D: Reviewing method of CT images. Images are viewed in all three planes simultaneously and they are linked to each other. Wherever cursor or cross-hair is placed on an image the other planes align to that point automatically.
  • 10Noncontrast CT (NCCT) is usually done for sinonasal inflammatory diseases unless there is a suspicion of extrasinus involvement. Contrast-enhanced CT (CECT) is generally recommended for the evaluation of tumors.
  • Demonstration of the pathology or the normal structures in multiple planes, such as coronal (most important), axial and sometimes sagittal is crucial for the surgical point of view.
  • Multiplanar reformations (MPR) were not possible in older CT scanners, hence direct acquisition of images in both axial and coronal planes were performed. The axial acquisition is done in supine position and coronal acquisition is usually done in prone position with hyperextension at neck. This doubled the radiation dose and increased artifacts due to motion (patient discomfort due to awkward positioning) and dental implants.
  • With the advent of MDCT, scenario changed and with the capability of rapid thin section acquisition it is now possible to acquire the entire sinonasal region in seconds. Once the volume data is acquired images can be reformatted in any plane. This technique negates the limitations of older scans.
  • The volume data can be post processed to generate various types of 3D images such as volume rendering technique (VRT), surface shaded display (SSD), etc.
  • The major limitation of CT scan is the radiation dose involved in the process. Roughly a standard dose CT PNS gives four times radiation dose than a standard three set plain radiographs.3 There are various methods available to reduce the radiation dose by maintaining the diagnostic quality. Two most important techniques which are widely used to reduce the radiation dose are—(1) tube current modulation, and (2) iterative reconstruction.
  • Tube current modulation is a type of automatic exposure control in which the radiation dose is adjusted in accordance with the patient habitus, attenuation of body part and the desired image quality. The implementation of this technique varies with the vendors and it can bring down the radiation dose up to 60%.
  • Iterative reconstruction is actually an older technique but the advances in computing have made it feasible only recently. Generally, it is added on to the existing filtered back projection method. It has the potential to bring down the radiation dose up to 85%.
 
Cone Beam CT
  • CBCT is getting wide acceptance as a point of care imaging tool and it is compact, portable and cheap compared to main stream CT scanners.
  • They use area detectors in contrast to multiple thin rows of detectors in conventional CT. The scanning of area of interest is completed in single rotation as compared to multiple rotations in conventional CT scanners (Table 1.4).
  • Major advantages of CBCT compared to conventional CT are superior spatial resolution and lesser radiation dose.11
Table 1.4   Advantages and disadvantages of cone-beam computed tomography (CBCT) compared to multidetector CT (MDCT).
Advantages
Disadvantages
  • Excellent spatial resolution
  • Bony structures are shown in great detail
  • Lower radiation dose
  • Poor contrast resolution due to increased scatter
  • Poor visualization of soft tissues
  • Poor temporal resolution
  • Limited Z-axis coverage
  • Lower dynamic range of the flat panel detectors
  • Contrast studies cannot be done
zoom view
Figs. 1.7A to C: Cone-beam computed tomography (CBCT) images in all three planes (A to C) showing deviated nasal septum with bony spur (arrow) and concha bullosa (asterisk) on the right side. Note that CBCT images are good for bony structures and but soft tissues are not well-visualized.
  • In spite of the above advantages it is currently not able to replace conventional CT for routine evaluation of sinonasal diseases because of various limitations.
  • The contrast resolution and signal-to-noise ratio (SNR) is poor in CBCT which is because of scattering effect on area detectors. Hence, it is good in evaluating only the high contrast structures, such as bones (Figs. 1.7A to C).
  • The lower dynamic range and poor temporal resolution of the flat panel detectors also pose major limitations.
 
MRI (Table 1.5)
  • Although CT is the preferred modality in the evaluation of sinonasal diseases, MRI has its own place in many situations and it is used as a complementary modality to CT.
  • The main advantages of MRI over CT are as follows:
    • Better contrast resolution and hence better characterization of soft tissues (differentiating tumor from secretions)12
      Table 1.5   Magnetic resonance (MR) planning.
      1. Coronal, axial and sagittal images
      2. Scan thickness 3–5 mm, interslice distance 1 mm
      3. Routine sequence T1W and T2W
      4. Contrast enhanced sequences (3D or 2D)
      5. T2W/FLAIR sequence for brain
      6. Fat suppressed used to evaluate complications of sinusitis or suspected neoplastic disease involve orbit and skull base
      zoom view
      Figs. 1.8A to D: Magnetic resonance imaging (MRI) of paranasal sinuses (PNS) for sinusitis. (A and B) Axial T1W image and T2W image showing diffuse mucosal thickening in bilateral maxillary sinuses with hyperintense content. (C and D) Coronal and axial postcontrast T1W image revealing diffuse mucosal enhancement.
    • Better evaluation of tumor spread outside the bony outline of sinuses
    • Perineural spread of tumor is best visualized on MRI
    • Spread of pathology in to orbit or cranium are also better evaluated on MRI.
  • Apart from routine morphological imaging on MRI using T1 and T2 weighted sequences, there are functional imaging techniques, such as diffusion weighted imaging (DWI) and perfusion imaging which can evaluate newer paradigms (Figs. 1.8 and 1.9).13
    zoom view
    Figs. 1.9A and B: Diffusion weighted MRI in sinusitis. Diffusion weighted MRI (b value 0) image showing hyperintense bilateral maxillary sinus mucosal thickening (asterisk on A), which on corresponding ADC image showing hyperintensity (asterisk on B) suggesting facilitated diffusion.
  • Although there are overlapping features on DWI and perfusion imaging to differentiate benign and malignant lesions, they can be a valuable addition nonetheless.
 
F-18 FDG PET-CT
  • PET-CT is another complementary modality mainly reserved for patients with malignant sinonasal masses to look for metastasis.
  • It is also used to look for postoperative residual or recurrent lesions in patients with malignancy.
 
CONCLUSION
Imaging is not indicated in vast majority of cases of inflammatory lesions of sinus. However, imaging plays a vital role in the diagnosis, preoperative evaluation and intraoperative guidance for surgeons in neoplastic, traumatic, developmental and specific situations in inflammatory conditions. CT is the workhorse in the evaluation of pathology complemented by MRI. With the ever-growing technical advancements in imaging, the value it adds to the management of patient is becoming indispensable.
REFERENCES
  1. Setzen G, Ferguson BJ, Han JK, et al. Clinical consensus statement: Appropriate use of computed tomography for paranasal sinus disease. Otolaryngol-Head Neck Surg. 2012;147(5):808–16.
  1. Cornelius RS, Martin J, Wippold FJ, et al. ACR Appropriateness Criteria Sinonasal Disease. J Am Coll Radiol. 2013;10(4):241–6.
  1. Abul-Kasim K, Strömbeck A, Sahlstrand-Johnson P. Low-dose computed tomography of the paranasal sinuses: radiation doses and reliability analysis. Am J Otolaryngol. 2011;32(1):47–51.