Arastoo Vossough, M.D., Ph.D. Associate Professor of Radiology

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1 Disorders of the Temporal Bone Arastoo Vossough, M.D., Ph.D. Associate Professor of Radiology

2 1st Branchial Cleft Cyst Remnant of 1 st branchial apparatus Rare Cystic lesions: I- around pinna II- connecting from angle of mandible/parotid to EAC May present as mass or drainage through sinus tract May get infected (sometimes 1 st clinical presentation) May be confused with an abscess no enhancement Facial nerve at risk during surgery MRI with heavily T2 weighted sequences may delineate tracts

3 History: Lots of cerumen can t see TM External Canal Osteoma

4 Exostosis

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7 External Auditory Canal Atresia More common in males May be bilateral Deformed pinna Bony and/or membranous Isolated or syndromic (e.g. hemifacial microsomia) Look for associated ear anomalies: Middle ear atresia/hypoplasia Ossicular fusion to middle ear wall Oval window atresia Aberrant possition of facial nerve (surgical risk) May later develop cholesteatomas over time

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11 Look for the facial nerve

12 EAC Atresia with Dysplastic Ossicles

13 Bony Fixation of the Malleus A B

14 Bony Fixation of the Incus A B C

15 Small Dysplastic Ossicles

16 Hemifacial Microsomia?

17 Hemifacial Microsomia

18 Acute Mastoiditis in Children

19 Coalescent Mastoiditis

20 Coalescent Mastoiditis

21 Mastoid Antrum

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24 3 year old s/p mastoidectomy

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35 Mastoiditis -> Lemierre s syndrome

36 Petrous Apicitis

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39 4 y/o girl transferred with mastoiditis and change in mental status

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42 Typanostomy (myringotomy) tube

43 Chronic Complications of Middle Ear Disease Chronic Otitis Media with Perforation (COM) Chronic Otitis Media with Cholesteatoma (COM)

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45 Epitympanum EAC TM Mesotympanum

46 Prussak space Scutum Pars flaccida of TM

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48 Cholesteatoma

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50 PORP: Partial Ossicular Reconstruction Prosthesis TORP

51 Congenital Middle Ear Cholesteatoma

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53 Congenital Middle Ear Cholesteatoma Congenitally trapped keratinized squamous epithelium, accumulation of cells and debris Rare (2%-4% of all cholesteatomas) No history or recurrent infections, trauma, or surgery May be found anywhere in middle ear (most commonly in anterior mesotympanum or perieustachian) Slowly grows over time May destroy ossicles and bone if grows

54 5 y/o girl

55 25 y/o External canal cholesteatoma

56 Sensorineural Hearing Loss Congenital and Early SNHL Osseous labyrinth malformations (Michel's aplasia, Mondini malformation,etc.) Membranous labyrinth malformations (complete, partial) Congenital infections (rubella, cytomegalovirus, etc.) Anoxia, birth trauma Ototoxic poisoning (streptomycin, thalidomide, quinine, etc.) Erythroblastosis fetalis (Rh incompatibility) Hyperbilirubnemia Cretinism Prematurity Syndromes (Usher, Pendred, Waardenburg, albinism, onychodystrophy, etc.)

57 Sensorineural Hearing Loss Delayed Sensorineural Hearing Loss Neoplasms (schwannoma, meningioma, lipoma, lymphoma, endolymphatic sac tumor, metastases, etc.) Enlarged endolymphatic sac and duct Infectious meningitis (bacterial, viral) Infectious labyrinthitis (viral, bacterial, spirochetal) Trauma (temporal bone fractures, acoustic trauma) Presbyacusis Endolymphatic hydrops (Meniere's disease) Autoimmune ear disease Ototoxic poisoning (aminoglycosides, diuretics, etc.) Vascular (stroke, vascular loop, AVM) Demyelinating diseases Cochlear otosclerosis/otospongiosis Labyrinthine obliteration (chronic labyrinthitis, Cogan's syndrome) Hemorrhage Perilymphatic fistula Sarcoid Surperficial siderosis Familial progressive SHNL Syndromes (Alport, Hurler, Hunter, Fabry, Klippel-Feil, etc.)

58 Congenital Anomalies Development of Otocyst Aplasia of labyrinth (Michel s aplasia) Division of Otocyst Common cavity malformation or cystic cochleovestibular anomaly Budding of Cochlea Cochlear aplasia or hypolasia Partitioning of Cochlea into 2¾ turns Incomplete partition (Mondini type malformation)

59 Congenital Anomalies Aplasia of Labyrinth (Michel s anomaly) Extremely rare Total absence of osseous and membranous labyrinth

60 Congenital Anomalies Common Cavity Malformation

61 Cystic cochleovestibular anomaly

62 Cochlear hypoplasia (bud)

63 Congenital Anomalies Incomplete partition of cochlea (Mondini-type Malformation) IP-II Most common (55%) of cochlear dysplasias Only 1½ turns in cochlea Middle and apical turns are fused No interscalal septa

64 Mondini Triad Common Error: Mondini Malformation is often applied to anything along spectrum of congenital labyrinthine anomalies Solution: Be descriptive and use hi-res CT and MRI to document all abnormalities

65 Mondini Triad

66 Congenital Anomalies Enlarged endolymphatic duct and sac syndrome (Enlarged vestibular aqueduct) Progressive stepwise decline in hearing in childhood and young adulthood Most common radiologically identifiable inner ear anomaly Vestibular aqueduct >1mm in diameter in middle of aqueduct Good rule of thumb: Compare it to the diameter of the posterior semicircular canals

67 Congenital Anomalies Enlarged endolymphatic duct and sac syndrome (Enlarged vestibular aqueduct)

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70 Cochlear Nerve Abnormalities Canal hypoplasia possibly secondary to cochlear nerve hypoplasia or absent cochlear nerve Follow-up with hi-res MR evaluation of cochlear nerve Does not benefit from cochlear implant From: Arastoo Vossough, PhD, MD, Imaging Evaluation of Sensorineural Hearing Loss Applied Radiology, January 2003

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72 Cochlear Nerve Hypoplasia

73 Narrow IAC

74 Narrow IAC

75 Cochlear Aperture Stenosis or Hypoplasia 9 year old with sensorineural hearing loss

76 46 year old male with hx of SNHLfor follow-up evaluation after cochlear implant. No benefit after implant.

77 Cochlear Aperture Stenosis or Hypoplasia Pre-Implant 46 year old male with Hx of SNHLfor follow-up evaluation after cochlear implant. Post Implant Glastonbury CM, et al, Imaging findings of Cochleaer Nerve Deficiency. AJNR 23: , April 2002

78 Temporal Bone Fractures Longitudinal fractures % - involve tympanic cavity - usually conductive hearing loss from ossicular disruption Transverse Fractures % - involve labyrinth - usually sensorineural hearing loss from inner ear or eight nerve damage

79 Temporal Bone Fractures Otic-capsule Involving

80 Otospongiosis Only affects humans Autosomal dominant inheritance w/variable expressivity Female predominance Peak 2 nd -3 rd decade Bilateral 80% Tinnitus may be presenting symptom Hearing Loss will eventually develop Always conductive component sometimes mixed

81 Otospongiosis Normal persistence of primary endochondral bone in middle layer of otic capsule Otospongiosiotic Phase replacement with spongy vascular new bone CT hypodense to otic capsule Otosclerotic Phase Osteoblastic proliferation Dense sclerotic bone deposition Emedicine Otosclerosis Author: Peter S. Roland, MD

82 Otospongiosis Fenestral (oval window) Cochlear (retrofenestral)

83 Otospongiosis Fenestral (oval window) 85% of otospongiosis 85% bilateral Early Decalcification along anterior margins of OW Embryologic fissula ante fenestrum Later: new bone effectively closes OW Complete obliteration in only 2% Fixates stapes footplate CHL Tx: Stapedectomy Cochlear (retrofenestral) Curtin and Som, Head & Neck Imaging, 4 th ed.

84 Otospongiosis Fenestral (oval window) 85% of otospongiosis 85% bilateral Early Decalcification along anterior margins of OW Embryologic fissula ante fenestrum Later: new bone effectively closes OW Compelte obliteration in only 2% Curtin and Som, Head & Neck Imaging, 4 th ed.

85 Otospongiosis Fenestral (Oval Window) Cochlear (retrofenestral) Conductive +/- SNHL Basilar turn first ( fourth turn ) Becomes sclerotic later than fenestral OS Only relative contraindication to cochlear implant evaluation Curtin and Som, Head & Neck Imaging, 4 th ed.

86 Otospongiosis Fenenstral Otospongiosis limited Ddx Cochlear Otospongiosis Paget Disease Osteogenesis Imperfecta Syphilis OI

87 Postmastoidectomy

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89 Labyrinthitis Viral, bacterial, spirochetal, autoimmune, traumatic SNHL with vertigo Complication: postinflammatory fibroosseous obliteration: Labyrinthitis ossificans Decreased MRI signal 2 to fibrous change Late: Ossification and obliteration of labyrinth

90 61 year old male with 15 month history of HA s, dizziness, and bilateral hearing losss

91 Labyrinthine Enhancement Schwannoma Autoimmune labyrinthitis Steroid responsive Viral labyrinthitis Perilymphatic fistula Syphylitic labyrinthitis Bacterial Labyrinthitis Middle ear or meningitis spread

92 Postoperative Labyrinthine Enhancement 58 year old woman status-post right acoustic neuroma resection

93 Labyrinthine Enhancement Enhancing inner ear structure: Inflammation or tumor?? High T1 signal on postcontrast images: Enhancement or intrinsic high T1 signal?

94 Labyrinthitis Ossificans

95 Paget s Disease

96 Fibrous Dysplasia

97 Perilymphatic fistula Abnormal communication between middle and inner ear Important cause of SNHL Characteristically fluctuating SNHL (possibly with vertigo/tinnitus) Increased risk for meningitis Congenital A/w congenital deformity of inner ear structures Otitis Media often occurs -> meningitis, labyrinthitis Worsen with trauma (including barotrauma) Acquired Trauma, neoplasm, infection

98 Demyelinating Disease

99 Vestibular Schwannoma

100 Intracochlear Schwannoma

101 Intracochlear Schwannoma

102 Intracochlear Schwannoma Contrast T1-weighted Noncontrast 3D FSE

103 CPA/Intracanalicular/Cochlear Meningioma

104 Endolymphatic sac tumor Papillary adenocarcinomas of the endolymphatic sac Sporadic or associated associated with von Hippel- Lindau syndrome From: Arastoo Vossough, PhD, MD, Imaging Evaluation of Sensorineural Hearing Loss Applied Radiology, January 2003

105 Cochlear Implant Childhood deafness Meningitis Idiopathic and iatrogenic (drug-induced) Congenital deformities Microphone and transducer worn externally Electrodes passed through round window into scala tympani Direct electrical stimulation of residual spiral ganglion cells of cochlear n. Bypassing destroyed hair cells

106 Cochlear Implant

107 Pre-Cochlear Implantation Imaging Evaluation Which type of device to use Which side to implant When surgery should be performed Cochlear patency Round window niche access Degree of mastoid aeration Contraindications

108 Pre-Cochlear Implantation Imaging Evaluation CT and MRI complementary Hypoplasia or acquired atrophy of cochlear nerve High-resolution T2-weighted MRI (FSE or CISS) Normal cochlear nerve = Facial Nerve CT Narrow internal auditory canal (< 2mm) Mastoiditis (Active Infection) Otospongiosis Cochlear Fibrosis/Ossification Choice of cochlear implant model Alter method of insertion Surgical Anatomy Facial N., Carotid A., Jugular V.

109 Cochlear Implantation