Goh -CONDUCTIVE HEARING LOSS FINAL Version.Pptx
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CONDUCTIVE HEARING LOSS DR JULIAN GOH DIAGNOSTIC RADIOLOGY TAN TOCK SENG HOSPITAL SINGAPORE
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Ossicles: fused / disrupted / absent / malforma on rd Dehiscence – 3 window Fluid or so ssue
Vascular structures
Abnormal interface with inner ear (oval / round windows) DECLARATIONS - NIL IP-III
Bone, so ssue, cerumen
ASHNR 2016 ASHNR 2016 IMAGING TECHNIQUES CT MSCT / CBCT • Double oblique • Wide window se ngs WIDE WINDOWS
MRI Pre & post contrast + DWI • Congenital cholesteatoma NARROW (BONE) • Cholesterol granulomas WINDOWS www.teachmesurgery.co • So ssue masses (extent, perineural spread) m ASHNR 2016 ASHNR 2016 EPITYMPANUM CHL – MIDDLE EAR
PERFORATED INTACT TM TM EAC MESOTYMPANUM
EUSTACHIAN NORMAL
TUBE INFLAMMATION RED HYPOTYMPANUM TRAUMA WHITE BLUE
ASHNR 2016 ASHNR 2016 INTACT TM - NORMAL CONGENITAL OSSICULAR CHAIN ANOMALIES • Usually in associa on with EAC anomalies • Isolated anomalies (with normal external ear) much less common1 • • Chronic effusions (chronic OME, Lack of progression, early age of onset dis nguish from fenestral otosclerosis NPC) • Unilateral (sporadic) / bilateral (gene c, AD) • Congenital ossicular anomalies Ossicular deformity: abnormal size, shape, • Oval window atresia orienta on • Otosclerosis Ossicular fixa on: bony bar from ossicles to middle ear wall Courtesy Berit Verbist, Leiden Courtesy Berit Verbist, Leiden
Swartz JD, Harnsberger HR. Imaging of the Temporal Bone, 3rd edi on. New York: Thieme 1998
ASHNR 2016 ASHNR 2016 OSSICULAR DEFORMITIES UNICRURAL STAPES CONGENITAL THICKENING • 2nd branchial arch dysplasia
• Distal incus (long, len cular
processes) 2nd branchial • Incudostapedial joint (ISJ) arch (Reichert’s discon nuity car lage) • Bony deformi es (hypoplas c, fibrous band)
• Stapes superstructure ASHNR 2016 ASHNR 2016 MONOPODAL/COLUMELLAR STAPES ABSENT DISTAL INCUS
Absent long & len cular processes (right)
Courtesy Jan Casselman Normal le side
ASHNR 2016 ASHNR 2016 ABSENT LENTICULAR PROCESS LEFT INCUS ABSENT LENTICULAR PROCESS LEFT INCUS
NORMAL ABSENT LENTICULAR PROCESS NORMAL ABSENT LENTICULAR PROCESS
ASHNR 2016 ASHNR 2016 INCUDOSTAPEDIAL JOINT (ISJ) DISCONTINUITY Middle aged male • Acquired > Congenital Chronic right o s, CHL • Congenital – hypoplasia / aplasia long process with disrupted ISJ Non-cholesteatomatous • Acquired – previous cholesteatoma; trauma#; resorp on erosion post-stapedectomy; non-cholesteatomatous erosion* • Can be seen in 15.7 % cases* Right len cular process • Severely retracted TM; osteoclas c resorp on; impaired vascular erosion supply Le len cular process intact
*Connor et al. Discon nuity of the incudo-stapedial joint within a fully aerated middle ear and mastoid on computed tomography: A clinico-radiological study of its ae ology and clinical consequence. Clin Radiol 2012 #Joel D Swartz, Seth Zwillenberg, Alan S Berger. Acquied Disrup ons of the Incudostapedial Ar cula on: Diagnosis with CT. Radiology 1989 ASHNR 2016 ASHNR 2016 OSSICULAR FIXATION • Bony bars • Calcified / ossifica on of suppor ng ligaments, tendons • Other structures e.g. persistent stapedial artery, dehiscent facial nerve Congenital footplate/OW thickening Normal footplate – double oblique
• Stapes foot plate fixa on most common FOOTPLATE – STAPES • Failure of annular ligament forma on • DDx – otosclerosis but hearing loss not progressive PATHOLOGY
Congenital closed footplate/OW Courtesy Jan Casselman
ASHNR 2016 ASHNR 2016 OSSIFIED STAPEDIUS TENDON INCUDOMALLEAL FUSION (NORMAL EXTERNAL EAR)
ASHNR 2016 ASHNR 2016 OSSIFIED MEDIAL INCUDOMALLEAL MALLEAL BAR LIGAMENT ASHNR 2016 ASHNR 2016 OTOSCLEROSIS • AD, variable penetrance; 3rd – 4th decades; F:M = 2:1 ANTERIOR MALLEAL BAR • CHL + SNHL; bilateral (70%) > unilateral • Fenestral (85-90%) & retrofenestral / cochlear (10-15%) • Early spongio c (ly c) phase followed by late sclero c phase • Fissula ante fenestrum, oval window; pericochlear
• CT. MRI – increased T2, enhancement. • Differen als: • Paget’s; osteogenesis imperfecta; syphilis; fibrous dysplasia PAGET’S FIBROUS DYSPLASIA
MRI of cochlear otosclerosis. J Goh, Chan LL, Tan TY. BJR 2002 Courtesy Berit Verbist, Valvassori. Imaging of otosclerosis. Otolaryngologic Clinics of North America 1993 Leiden
ASHNR 2016 ASHNR 2016 COCHLEAR CLEFT WHY IMAGE? • Other causes of unilateral CHL • Surgical issues: • Extent (cochlear implants) • Round window involvement • Oval window oblitera on • Facial nerve posi on • Ossicular status • Malleus fixa on • Incus defects (inflammatory erosions; discon nuity) • Chronic o s media • PIOF (tympanosclerosis) • Gusher anomaly (e.g. IP – III)
ASHNR 2016 ASHNR 2016 OVAL WINDOW ATRESIA
• Stapes blastema fails to contact o c capsule ! failed oval window development • Displaced VII nerve
RETROFENESTRAL; ROUND FENESTRAL WINDOW INVOLVEMENT ASHNR 2016 ASHNR 2016 Axial image showing incudostapedial joint and OVAL WINDOW ATRESIA posteriorly angulated incus and stapes. Stapes fused to • CT pyramidal eminence and • Atre c window (coronal plane) facial nerve canal • Displaced facial nerve • Stapes abnormali es
• Surgical issues: Atre c oval window; displaced VII Coronal image showing • Facial nerve posi on nerve absent oval window and • Presence / absence of stapes superstructure inferiorly displaced facial nerve
Zeifer B. Sabini P, Sonne J. Congenital absence of the oval window: Radiologic diagnosis and associayed anomalies. AJNR 2000; 21 : 322-327 Booth TN, Vezina LG, Gerald Karcher, Dubovsky EC. Imaging and clinical evalua on of isolated atresia of the oval window. AJNR 2000; 21 : 171-174 Lambert PR. Congenital absence of the oval window. Laryngoscope 1990; 100: 37 – 40 Jahrsdoerfer RA. Congenital absence of the oval window. ORL J Otorhinolaryngol Relat Spec 1977; 84: 904 – 914
ASHNR 2016 ASHNR 2016 MIDDLE EAR – WHITE TM CONGENITAL CHOLESTEATOMA • Young pa ent; normal middle ear & mastoid pneuma sa on; white avascular mass. No h/o inflamma on or discharge • Tympanosclerosis • Posi on: meso/hypotympanum; medial to ossicles • Theories: • Congenital • Congenital ectodermal rest • Failure of regression of epidermoid cholesteatoma inclusion • 30% have CHL • Associa on with EAC dysplasia
ASHNR 2016 ASHNR 2016 CONGENITAL CHOLESTEATOMA CONGENITAL CHOLESTEATOMA ASHNR 2016 ASHNR 2016 FACIAL NERVE SCHWANNOMA
Loca ons: CPA – IAC; Temporal bone (geniculate, tympanic, mastoid) Atypical VII n weakness/ twitching + CHL
• Tubular enlargement facial nerve canal • Smooth, scalloped borders • MRI: intense enhancement post- Gd
De Foer et al. Neuroradiology 2010
ASHNR 2016 ASHNR 2016 LEFT JACOBSON’S SCHWANNOMA MIDDLE EAR – BLUE TM
• Cholesterol granuloma
• Dehiscent jugular bulb
• “Glue ear”
Courtesy Drs Raymond Ngo, Amit Karandikar
ASHNR 2016 ASHNR 2016 CHOLESTEROL GRANULOMA CHOLESTEROL GRANULOMA • Chronic inflamma on • Obstruc on – vacuum hypothesis • Anywhere in pneuma sed temporal • bone (middle ear/mastoid; petrous Obstruc on primary cause. apex) • Middle ear: Eustachian tube dysfunc on ! repeated obstruc on & reduced pressure ! repeated haemorrhage & granula on ssue • Expansile middle ear lesion, • Petrous apex: obstruc on of channels from petrous apex cells blue drum • • Exposed marrow theory M = F. Younger – middle-aged • Hyperplas c mucosa invades bone, exposes marrow ! repeated adults; late symptom onset haemorrhage • Tinnitus, + CHL • • DDx: glomus; dehiscent jugular Trapped blood, chronic inflamma on. Cholesterol crystals in fluid bulb; “glue ear” • Foreign body reac on with fibrosis, vessel prolifera on. ASHNR 2016 ASHNR 2016 CHOLESTEROL GRANULOMA CHOLESTEROL GRANULOMA
• CT • Mimics granula on ssue • Expansile, smooth scalloped borders + ossicular erosion
T1 T2 • MR • high T1 pre-contrast (methaemaglobin), high T2. • No real enhancement
T1 + C DWI
ASHNR 2016 ASHNR 2016 CHOLESTEROL GRANULOMA
ASHNR 2016 ASHNR 2016 DEHISCENT JUGULAR BULB RED TM
• Trauma • Vascular anomalies • Aberrant ICA • Persistent stapedial artery
• Paragangliomas
PULSATILE TINNITUS ASHNR 2016 ASHNR 2016 PARAGANGLIOMAS PARAGANGLIOMAS CT • Benign, highly vascular. From extra-adrenal neuroendocrine system. F > • Isoa enua ng so ssue masses (NECT), intense enhancement (CECT). Permea ve bone changes M; 2/3 in 4th to 6th decades • Sporadic / familial (AD, variable penetrance). MRI • Pulsa le nnitus, CHL, ver go + cranial nerve palsies. Red TM • Low T1, high T2, intense enhancement. “Salt & pepper” appearance (haemorrhage). Flow voids (lesions > 2cm) • CHL – engulf (not erode) ossicular chain • Types: Angiography • Jugular – Arnold’s nerve, jugular foramen (permea ve erosion of bony margins) • Intense tumour blush, early draining veins • Tympanic – Jacobson’s nerve, cochlear promontory • Jugulotympanic Scin graphy • Indium-111 octreo de accumula on
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Large tympanic paragaglioma growing along Eustachian tube and EAC; “salt & pepper” Courtesy Dr Wendy Smoker
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CT images in the (A) coronal and (B) axial planes showing a jugulo- tympanicum lesion (red arrows) engulfing, but not eroding, the ossicles ASHNR 2016 ASHNR 2016 ABERRANT ICA
Aberrant ICA on promontory. ‘Steno c’ segment at entry into horizontal canal
ASHNR 2016 ASHNR 2016 INNER EAR –SEMICIRCULAR CANAL DEHISCENCE PERSISTENT STAPEDIAL ARTERY (SCD) • “3rd window”. Superior >> posterior • Pseudo-CHL (bone thresholds high) • Autophony; nnitus; hyperacusis; ves bular symptoms (Tullio’s phenomenon – sound-induced ver go + nystagmus) • Focal dehiscence on CT + ves bular symptoms => semicircular canal dehiscence
ASHNR 2016 ASHNR 2016 SEMICIRCULAR CANAL DEHISCENCE (SCD) • Usually unilateral. • Incidence ~ 2%. 2.1% local study (10/481), all SSC • Focal dehiscence > 2 mm size on coronal CT for superior semicircular canal (SSC) Poschl’s • Best seen in: (SSC) • Poschl’s plane – SSCD • Stenver’s plane, axial CT – PSCD • Extreme thinning mimics dehiscence. Correlate with symptoms! Stenver’s (PSC) SC Loke, JPN Goh. Incidence of superior semicircular canal dehiscence in Singapore. BJR 2009 Williamson et al. Otolaryngol Head Neck Surg 2003. Coronal computed tomography prevalence of superior semicircular canal dehiscence. ASHNR 2016 ASHNR 2016
large VA, endolymphatic sac not visible
IP – III
POU3F4 muta on
widened IAC fundus, no modiolus, corkscrew cochlea
R L
Courtesy Berit Verbist, Leiden
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NORMAL RED TM
• Congenital ossicular • Trauma anomalies • Vascular anomalies • Oval window • Aberrant ICA atresia • Persistent • Otosclerosis stapedial artery • Non-glomus • Paragangliomas enlarged nerve canals tumours
BLUE TM WHITE TM
• Dehiscent jugular • Tympanosclerosis bulb
• Congenital • Cholesterol cholesteatoma granuloma
Courtesy Berit Verbist, Leiden
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