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Imaging of paranasal sinuses RV

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Imagingof paranasal sinuses ,inflammatory , benign and neoplastic lesions anatomical variants

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Imaging of paranasal sinuses RV

  1. 1. IMAGING OF PARANASAL SINUSES Dr Roshan Valentine PG Resident Dept of Radiodiagnosis St Johns Hospital , Bangalore
  2. 2. EMBRYOLOGY • At birth, the ratio of the volume of the facial skeleton to the volume of the cranial vault is about 1:7. • Development of the paranasal sinuses leads to increase in the ratio • 4 major sinuses : Maxillary , ethmoid , sphenoid and frontal sinuses
  3. 3. • Maxillary , ethmoid and frontal sinuses develop from invaginations of the nasal cavity into bones • Sphenoid sinus forms by closure of sphenoethmoidal recess • Maxillary sinus - forms during 3rd fetal month • Primary pneumatisation and secondary pneumatisation • Sphenoid and frontal sinus – develop during Pre natal 4th mnth then undergo sec pneumatisation EMBRYOLOGY
  4. 4. • Frontal sinus not radiologically visible till post natal 6 yrs • Ethmoid sinus during post natal 5th month • Growth continues till adulthood EMBRYOLOGY
  5. 5. ANATOMY • Air containing cavity in certain skull bones • They are lined by mucosa similar to that of the nasal cavity – pseudo stratified ciliated columnar epithelium SIGNIFICANCE • Lighten the skull & facial bones • Contributes to vocal resonance • Collapsible framework that helps the brain to protect from blunt trauma
  6. 6. PHYSIOLOGY • Side to side cyclic variation in thickness of nasal mucosa • Signal intensity of mucosal lining of nasal cavity & ethmoid sinuses also vary. • During oedematous phase of nasal cycle, mucosal signal intensity on T2 is similar to mucosal inflammation • No cyclic variation in frontal, maxillary or sphenoid sinus mucosa
  7. 7. Sinuses Status at Birth First Radiologic al evidence Reaches Adult size by Maxillary sinus Present at birth 4-5 months after birth 15 years Ethmoid sinus Present at birth 1 year 12 years Sphenoid sinus Not Present 4 years 15 years – adult age Frontal Sinus Not Present 6 years Size increases until teens
  8. 8. MAXILLARY SINUS • Antrum of highmore • Pyramidal in shape • Present at birth as a rudimentary sinus • First radiological evidence is at 4-5 months after birth • Reaches adult size by 15 years • On average, it has capacity of 14.75 ml
  9. 9. MAXILLARY SINUS DRAINAGE • Seen high up in the medial wall • Does not open directly into the nasal cavity, but opens into post. part of ethmoidal infundibulum, via hiatus semilunaris into middle meatus. • The infundibulum is the air passage that connects the maxillary sinus ostium to the middle meatus. • Unfavourable for natural sinus drinage • Accessory ostium – 30 % cases
  10. 10. FRONTAL SINUS • Situated between the outer & inner table of frontal bone • Funnel shaped • Two sinuses on either side • Asymmetrical • Intervening bony septum which may be thin or deficiency
  11. 11. FRONTAL SINUS • Not present at birth • First radiological evidence is at 6 years • Reaches adult size after puberty • OSTIUM : posteromedial floor of the sinus (most dependent part). • Open into frontal recess or naso frontal duct
  12. 12. FRONTAL SINUS FRONTAL RECESS • Hour glass like narrowing • Narrowest anterior air channels – prone for infection • obstruction subsequently results in loss of ventilation and mucociliary clearance of the frontal sinus
  13. 13. SPHENOID SINUS • Occupies the body of sphenoid • Right & left, seperated by a thin strip of bony septum (like frontal sinus) • Ostium opens into spheno ethmoidal recess • Relations of the sinus are very important, esp during the surgical approach of pituitary gland
  14. 14. SPHENOID SINUS
  15. 15. SPHENOID SINUS RELATIONS Anterior Part • Roof – olfactory tract, optic chiasma & frontal lobe • Lateral – optic nerve, internal carotid artery & maxillary nerve Posterior Part • Roof – Pituitary gland in sella turcica • Lateral – Cavernous sinus,ICA & Cranial nerves III, IV, VI & all divisions of V
  16. 16. ETHMOID SINUS • Thin walled air cavities in the lateral masses of the ethmoid bone • Occupy the space between the upper third of the lateral nasal wall and the medial wall of orbit • Clinically divided into anterior ethmoidal air cells & posterior ethmoidal air cells, by basal lamella (lateral attachment of middle turbinate to lamina papyracea)
  17. 17. ETHMOID SINUS DRAINAGE • Anterior : Recess of hiatus semilunaris and middle meatus via ethmoid bulla • Posterior : Sup meatus and SE recess • Present at birth • Reaches adult size by 12 yrs • First radiological evidence seen at 1 year
  18. 18. SPHENOID SINUS
  19. 19. ETHMOID SINUS RELATIONS Roof – formed by the anterior cranial fossa Lateral wall - orbit Medial wall – nasal cavity Thin paper like bony part of the ethmoid separating the air cells from the orbit, Called LAMINA PAPYRACEA, can be easily destroyed leading to spread of ethmoidal infections into the orbit Optic nerve forms a close relationship with the posterior ethmoidal cells & is at risk during ethmoidal surgery
  20. 20. OSTEOMEATAL COMPLEX • Key anatomic area for surgeons • Blockage prevents mucociliary clearance – stagnation of secretions – recurrent or chronic sinusitis
  21. 21. OSTEOMEATAL COMPLEX BOUNDARIES • Medially :middle turbinate, • Posteriorly and superiorly : basal lamella • Laterally : lamina papyracea. • Inferiorly and anteriorly the omc is open.
  22. 22. OSTEOMEATAL COMPLEX STRUCTURES • Maxillary sinus ostium • Ethmoidal bulla • Frontal recess • Uncinate processus • Infundibulum • Hiiatus semilunaris • Middle meatus
  23. 23. NORMAL ANATOMY NASAL STRUCTURES Nasal Septum • Bone and cartilage • Midline structure Lateral wall • Superior , middle and inferior tubrinates 3 air passages • Superior , middle and inferior meatus
  24. 24. NORMAL ANATOMY INFERIOR TURBINATES • Lower most projection with extension into nasopharynx • Enlarged in DNS and allergic rhinits NASOLACRIMAL DUCT • Tubular structure in the lateral wall • Opens into inferior meatus underneath inf turbinate
  25. 25. NORMAL ANATOMY MIDDLE TURBINATE • Attach to the skull base lateral to cribriform plate • Basal lamella – part of middle turbinate attached to ethmoid complex
  26. 26. NORMAL ANATOMY DRAINING PATHWAYS • Anterior draining pathways • Posterior draining pathways
  27. 27. NORMAL ANATOMY ANTERIOR DRAINING PATHWAYS • Osteomeatal complex – air passage between frontal , ant ethmoid and maxillary sinus Components: Frontal recess , ethmoid infundibulum , hiatus semilunaris and middle meatus
  28. 28. NORMAL ANATOMY MIDDLE MEATUS • b/w middle turbinate and uncinate process • Uncinate process: superior extension of the medial wall of maxillary sinus • Agger Nasi : Most anterior cells in ant ethmoidal sinus complex • Hiatus semilunaris – Crevice between uncinate process and ethmoidal bulla • Ethmoidal infundibulum : maxillary ostium to middle meatus , b/w uncinae process and lamina papyracea
  29. 29. NORMAL ANATOMY INFERIOR MEATUS • Opening of the drainage channel of NLD
  30. 30. NORMAL ANATOMY POSTERIOR DRAINAGE PATHWAYS • Draining pathways of sphenoid and posterior ethmoidal sinus • They drain via sphenoethmoidal recess into superior meatus • B/w anterior sphenoid sinus wall and posterior wall of ethmoid sinus air cells
  31. 31. ANATOMICAL VARIANTS CONCHA BULLOSA • Aerated middle turbinate • Obstruct the middle meatus and infundibulum • Concha Bullosa – Pneumatised bulbous segment of the middle turbinate • Lamellar concha – Only the attachment portion of the middle turbinate AERATED CRISTA GALLI AERATED ANTERIOR CLINOID PROCESS
  32. 32. ANATOMICAL VARIANTS DEVIATED NASAL SEPTUM • Can compress middle turbinate laterally • Narrow the middle meatus • Bony spurs : can obstruct OMC
  33. 33. ANATOMICAL VARIANTS PARADOXICAL MIDDLE TURBINATE • Middle turbinate project laterally narrowing middle meatus
  34. 34. ANATOMICAL VARIANTS UNCINATE PROCESS Superior edge can • Deviate medially – obstruct middle meatus • Deviate laterally to compromise the infundibulum • Fusion with the medial orbital wall – endanger orbital contents while uncinectomy is done
  35. 35. ANATOMICAL VARIANTS UNCINATE PROCESS • Type I – Insertion of UP into LP directly/ indirectly (via an anterior ethmoidal cell) • Type II –Insertion of UP into the skull base (SB) • Type III – Insertion of UP into middle turbinate • Type IV – UP lying free in the middle meatus (Free type).
  36. 36. ANATOMICAL VARIANTS UNCINATE PROCESS PNEUMATISATION
  37. 37. ANATOMICAL VARIANTS HALLER CELLS • Infraethmoid air cells extending along the roof of maxillary sinus and lateral to the uncinate process • Narrows the infundibulum
  38. 38. ANATOMICAL VARIANTS ONODI CELL • Lateral and posterior extensions of the posterior ethmoid air cells , superolateral to the sphenoid sinus • Lie in close relation to the optic nerve
  39. 39. ANATOMICAL VARIANTS PROMINENT ETHMOID BULLA • Largest of the ethmoid air cells • Obstruct the middle meatus and infundibulum
  40. 40. ANATOMICAL VARIANTS MEDIAL DEVIATION OR DEHISCENCE OF THE LAMINA PAPYRACEA • May be either congenital or the result of prior facial trauma. • It occur most often at the site of the insertion of the basal lamella into the lamina papyracea, thus rendering this portion of the lamina papyracea most delicate • Orbit at risk
  41. 41. ANATOMICAL VARIANTS ETHMOIDAL ROOF VARIATIONS • Keros 3 types • Length of the lateral lamella of cribriform plate – thinnest part of entire skull base • Danger of penetration of of the lateral lamella Type 1: 1-3mm deep Type II : 4-7mm Type III : 8-16mm
  42. 42. ANATOMICAL VARIANTS AERATED CRISTA GALLI • When aeration of the normally bony crista galli occurs the aerated cells may communicate with the frontal recess, and obstruction of this ostium. • To avoid unnecessary surgical extension into the anterior cranial vault, it is important to recognize an aerated crista galli and differentiate it from an ethmoid air cell.
  43. 43. IMAGING MODALITIES
  44. 44. IMAGING MODALITIES CONVENTIONAL RADIOGRAPHY • Lateral view • Caldwell View • Waters View • Submento vertical view CT Gold standard. Coronal & axial sections MRI • MRI is predominantly used for pre and post operative management of naso sinus malignancy • The chief disadvantage of MRI is its inability to show the bony details of the sinuses, as both air and bone give no signal
  45. 45. WATERS VIEW • The patient’s nose and chin are placed in contact with the midline of the cassette holder. • The head is then adjusted to bring the orbito- meatal baseline to a 45-degree angle to the cassette holder. • Maxillary sinus ,frontal sinus , anterior ethmoidal air cells , inferior orbital rims , and orbital floors
  46. 46. CALDWELL VIEW • The head is positioned so that the orbito- meatal baseline is raised 15 degrees to the horizontal • Frontal sinus and posterior ethmoidal air cells
  47. 47. LATERAL VIEW • Mediansagittal plane parallel to casette • Inter-orbital line is perpendicular to the Bucky • Frontal, maxillary and sphenoid sinus
  48. 48. SUBMENTO VERTEX VIEW • Mainly for the sphenoid sinus • Infraorbito-meatal (Frankfort line) parallel to the casette
  49. 49. COMPUTED TOMOGRAPHY • Modality of choice • Protocol : Thin slices and MPR • Axial plane : parallel to the inferior orbitomeatal plane • Extent : superior wall of frontal sinus to hard palate • Bone and soft tissue window • Patency of Osteometal complex and other pathways : Lung Window • Contrast : neoplasm and its intra acranial extension , acute infections,
  50. 50. COMPUTED TOMOGRPAHY PRE REQUISITES • Course of medical therapy to eliminate reversible mucosal inflammation • Reduce nasal congestion 15 mins prior to the study • Thus improve the display of the fine bony architecture and any irreversible mucosal disease
  51. 51. COMPUTED TOMOGRPAHY • Coronal View: Primary image orientation for evaluation of the sinonasal tract in all patients with inflammatory sinus disease who are endoscopic surgical candidates
  52. 52. COMPUTED TOMOGRPAHY
  53. 53. COMPUTED TOMOGRPAHY AXIAL IMAGE • Complements coronal image • For anterior and posterior sinus walls • Visualising fronto ethmoid junction and sphenoethmoid recess
  54. 54. MR IMAGING • Spread of pathology into brain and orbit • Superior soft tissue extension • Contrast : tissue characterization • Skull base and posterior fossa
  55. 55. INFLAMMATORY SINUS DISEASE ACUTE SINUSITIS • Superinfection of obstructed sinus • Secretions favour growth for bacteria • The hallmark of acute sinusitis is air fluid level on plain x-ray and CT
  56. 56. CHRONIC SINUSITIS • Hypertrophic mucosa • Polypoid changes with atrophy and fibrosis • Sinus secretions in acute state: 10-25HU • Chronic sinusitis : 30-60HU (mucoid secretions) • Facial bones undergo thickening and sclerosis adjacent to the inflamed mucosa Hyperdense Secretions • Inspissated secretions • Fungal sinusitis • Hemorrhage CHRONIC SINUSITIS
  57. 57. CHRONIC SINUSITIS
  58. 58. Sonkens Et al patterns of chronic sinusitis • Infundibular pattern • Ostiomeatal unit pattern • Sphenoethmoidal recess pattern • Sinonasal polyposis pattern • Sporadic/unclassified pattern Helps the surgeon in planning FESS as the rational is to restore the flow of sinus secretion via their natural pathways CHRONIC SINUSITIS
  59. 59. INFUNDIBULAR PATTERN • Maxillary sinus , infundibulum • Occur due to mucosal thickening, polyp in that location , Haller cells OSTIOMEATAL UNIT PATTERN • Middle meatus obstruction • Changes in frontal, anterior ethmoid and maxillary sinus • Cause : Mucosal thickening , polyps , concha bullosa , DNS SPHENOETHMOIDAL RECESS PATTERN • SE recess is blocked • Changes in I/L sphenoid and post ethmoidal air cells CHRONIC SINUSITIS
  60. 60. SINONASAL POLYPOSIS PATTERN • Both nasal cavities and sinuses are filled • Mix of all three patterns SPORADIC/UNCLASSIFIED PATTERN • No specific kind of obstruction • Mucocele , retention cysts or post operative changes are there CHRONIC SINUSITIS
  61. 61. SINONASAL POLYPOSIS • Nonneoplastic, inflammatory swelling of sinonasal mucosa • Involves nasal cavity and PNS • Predominantly along lateral nasal wall and roof of nasal cavity • Dx clue : Polypoid masses involving nasal cavity & paranasal sinuses mixed with chronic inflammatory secretions
  62. 62. SINONASAL POLYPOSIS IMAGING FINDINGS • NECT : Polypoid soft tissue density with bone remodeling/erosions Hyperdense with inc protein content and dec water content • CECT : Peripheral enhancement
  63. 63. SINONASAL POLYPOSIS MRI T1WI • Fresh mucus (high water content) is hypointense • Heterogenous SI : polyps mixed with various ages of mucus T2WI • Fresh mucus is hyperintense • Chronic, inspissated mucus can appear low signal (mimics air) T1WI C+ • Thin mucosal enhancement between polypoid soft tissue lesions without central enhancement
  64. 64. SINONASAL SOLITARY POLYP
  65. 65. • Secondary to obstructed mucus drainage • Expanded and remodeled sinuses – obstructed and contain secretions • Frontal > ethmoid sinus > maxillary sinus • Infected mucocele – Mucopyocele • CT: expanded sinus with intact walls containing mucoid and soft tissue densities • Remodelling of sinus can occur • MR : Depends on the nature of the secretion Peripheral enhancement MUCOCELE
  66. 66. NLD MUCOCELE
  67. 67. INFLAMMATORY SINUS DISEAS 3 TYPES • Allergic fungal rhinosinusitis • Invasive fungal sinusitis • Non invasive chronic fungal sinusitis FUNGAL SINUSITIS
  68. 68. INFLAMMAORY SINUS DISEASE ALLERGIC FUNGAL SINUSITIS • Allergic response to fungal elements in atopic pts • CT : Diffuse mucosal thickening involving multiple sinuses with central hyperdense content and peripheral hypodensity • MRI :Central content is hypo on T1 and T2 • Wall destruction not seen • Central or punctate calcification FUNGAL SINUSITIS
  69. 69. INFLAMMAORY SINUS DISEASE ALLERGIC FUNGAL SINUSITIS • Allergic response to fungal elements in atopic pts • CT : Diffuse mucosal thickening involving multiple sinuses wit central hyperdense content and peripheral hypodensity • MRI :Central content is hypo on T1 and T2 • Wall destruction not seen • Central or punctate calcification FUNGAL SINUSITIS
  70. 70. INFLAMMAORY SINUS DISEASE
  71. 71. INFLAMMATOY SINUS DISEASE INVASIVE FUNGAL SINUSITIS • Immunosuppressed individuals • Mucor, aspergillus or fusarium • CT: Opacification of sinuses by secretions and mucosal hypertrophy • Destruction of the boney wall • Spread of infection into orbits , cavernous sinus or brain FUNGAL SINUSITIS
  72. 72. INFLAMMATORY SINUS DISEASE NON INVASIVE CHRONIC FUNGAL SINUSITIS • Chronic, noninvasive form of fungal sinus infection in which material within sinonasal cavity is colonized by fungus • Ball of fungus • MC – Maxillary sinus FUNGAL SINUSITIS
  73. 73. NON INVASIVE CHRONIC FUNGAL SINUSITIS CT FINDINGS CECT • Thickened, inflamed mucosa at periphery of sinus may enhance • Opacification or focal mass within sinus lumen • Central areas of high density ± calcification • Thick, sclerotic bony sinus walls from chronic inflammation MR FINDINGS T1WI • Variable signal material in affected sinus • Usually ↓ T1 signal due to absence of free water in thick, solid, mycetomatous mass T2WI • Hypointense mass from macromolecular protein binding may be mistaken for air • T1WI C+ • Inflamed peripheral mucosa may enhance FUNGAL SINUSITIS
  74. 74. GRANULOMATOUS DISEASE • Actinomycosis, tuberculosis, syphilis, leprosy, rhinoscleroma, rhinosporidiosis, sarcoidosis, Wegener’s granulomatosis, midline granuloma, leishmaniasis and yaws • Non specific findings -Soft tissue masses and focal erosions • Leprosy,WG, Cocaine : septal thickening or erosions
  75. 75. BENIGN TUMOR AND TUMOR LIKE LESIONS • Sinonasal osteoma • Sinonasal fibrous dysplasia • Sino nasal ossifying fibroma • Juvenile Angiofibroma • Sinonasal papilloma
  76. 76. SINONASAL OSTEOMA • MC benign tumor • benign, well-defined, slow-growing, bone-forming tumor from wall of paranasal sinus & protrudes into sinus lumen • Frontal & ethmoid > > > maxillary & sphenoid • Larger osteomas can cause sinus opacification by ostia obstruction • Orbital mass effect by extraconal extension
  77. 77. SINONASAL OSTEOMA
  78. 78. SINONASAL FIBROOSSEOUS LESIONS • Spectrum of disorder a purely fibrotic lesion at one end and a dysplastic bony lesion at the other • Fibrous tissue replacing normal medullary bone • Diagnostic Clue FD : Ill-defined expansion of diploic space with “Ground-glass” density Ossifying Fibroma : Well-demarcated, expansile mass with soft tissue density (fibrous) central area surrounded by ossified rim
  79. 79. FD
  80. 80. OF
  81. 81. SINONASAL INVERTED PAPILLOMA • Benign epithelial tumor of nasal mucosa with histology showing epithelium proliferating into underlying stroma • Dx Clue : Mass along lateral nasal wall centered at middle meatus ± extension into antrum with local bone remodeling & obstructive sinus disease • MC : Lateral nasal wall with extension into adjacent sinus
  82. 82. Modified Krause staging A. Inverted papilloma (IP) confined to the nasal cavity, ethmoid sinus, or medial maxillary wall. B. Inverted papilloma (IP) with involvement of any maxillary wall (other than the medial wall) or frontal sinus or sphenoid sinus C. Inverted papilloma with extension beyond the paranasal sinuses A- endoscopic resection B – Radical approach PAPILOMMA
  83. 83. JUVENILE ANGIOFIBROMA • Benign, vascular, nonencapsulated, locally invasive nasal cavity mass • Centered in posterior nasal • Extends into nasopharynx, pterygopalatine fossa (PPF), infratemporal fossacavity near SPF • Can spread across skull base and a combination of CT (to assess bone destruction;) and contrast-enhanced MRI (to assess soft tissue extent;) may be required • Dx clue : Intensely enhancing mass originating at sphenopalatine foramen (SPF) in adolescent male
  84. 84. JAF
  85. 85. MALIGNANT TUMOR OF PNS • Malignant epithelial tumor from sinus surface epithelium with squamous cell or epidermoid differentiation • MC : Maxillary antrum • Dx clue : Aggressive antral soft tissue mass with invasion & destruction of sinus walls • Role of radiologist : presurgical tumor map of spread
  86. 86. MALIGNANT TUMOR OF PNS • Imaging findings CT : Solid, moderately enhancing mass with aggressive bone destruction +/- necrosis MRI : • T1 : Intermiediate , intratumoral H’age shows inc signal • T2: ↓ T2 signal due to ↑ cellularity & ↑ nuclear:cytoplasmic ratio • CE: Enhancement typically mild to moderate; diffuse, but heterogeneous • PET : Avid uptake of F18 FDG
  87. 87. MALIGNANT TUMOR OF PNS
  88. 88. MALIGNANT TUMOR OF PNS
  89. 89. MALIGNANT TUMOR OF PNS • OHNGREN’S LINE : Connecting the medial canthus of the eye to the angle of the mandible • Divide the maxillary sinus into • Anteroinferior portion infrastructure)- good prognosis • Superoposterior portion(suprastructure) - poor prognosis – early extension to skull base , orbits , infratemporal fossa
  90. 90. STAGING OF CANCER (AJCC 7TH ED)
  91. 91. STAGING OF CANCER (AJCC 7TH ED)
  92. 92. STAGING OF CANCER (AJCC 7TH ED)
  93. 93. OLFACTORY NEUROBLASTOMAS • Olfactory neuroepithelioma , Esthesioneuroblastoma • Polypoid tumor with profuse bleeding • Age : 11-22yrs and 50-60 years of age • CECT : homogenous mass with moderate enhancement • Cysts at intracranial tumor-brain margin • Dx clue : Dumbbell-shaped mass with upper portion in anterior cranial fossa, lower portion in upper nasal cavity, & “waist” at level of cribriform plate • Peripheral tumor cysts at intracranial tumor- brain margin is highly suggestive of diagnosis of ENB
  94. 94. Multiplanar Sinus CT: A Systematic Approach to Imaging Before Functional Endoscopic Sinus Surgery, AJR 2010; 194:W527–W536 • Sinus drainage pathways – OMC , sphenoidalostia , sphenoethmoidal recess, frontal recess • Anatomic variants : Nasal septum , OMC variants • Critical variants : Cribriform plate dehiscence of lamina papyracea , focal bony dehiscence of sphenoidal sinus . • Soft tissues : orbital , cranial extension

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