Download congenital hearing loss

C O N G E N I TA L H E A R I N G L O S S
Hear the Signs
Atat C 1 ║ Yazbek S 1 ║ Haddad A 1 ║ Abi Khalil S 1 ║ Slaba S 1 ║ Robson C 2,3
1
Hotel Dieu de France Hospital, Beirut, Lebanon
2
Boston Children's Hospital, Boston, MA
eEdE-126
3
Harvard Medical School, Boston, MA
DISCLOSURES
Atat C, Yazbek S, Haddad A, Abi Khalil S, Slaba S: No disclosures
Robson CD: Royalties Elsevier Inc.
OBJECTIVES
• Develop a structured approach to reading a temporal bone CT for
Congenital Hearing Loss (CHL)
• Describe the cases where an MRI of the inner ear structures is
recommended
• Know the etiologies of CHL where a cochlear implant should be avoided
HOW TO BROWSE THE CASES
• We recommend a structured approach starting with
the EAC and ending with the brain parenchyma
• You can also go straight to the area of interest by
clicking directly on it
• In most cases, a hint can be solicited by clicking on
Hint
Washington Otology ©
Click on the area you want to explore.
Washington Otology ©
External Auditory Canal
Washington Otology ©
Middle Ear
Washington Otology ©
Inner Ear
Washington Otology ©
Cerebellopontine Angle – Brain Parenchyma
EXTERNAL AUDITORY CANAL
Right external auditory canal atresia
Hypoplastic MEC
Malformed ossicles
Hint
Congenital External and Middle Ear Malformation (CEMEM)
External Auditory Canal Atresia and Stenosis
Best imaging tool: T-bone CT with 2D reconstruction
• Malformed pinna: Severity of microtia approximates severity of
CEMEM.
• Variable severity, from EAC atresia with absent tympanic plate and
severe middle ear and ossicular anomalies to mild EAC stenosis with
mild middle ear and ossicular anomalies
• EAC anomalies are associated with malformed middle ear cavity &
contents (EAC & MEC structures are derived from branchial apparatus
while inner ear structures are derived from otic vesicle).
• Anomalies of inner ear unusual in CEMEM unless syndromic.
Rt EAC atresia; tympanic plate absent
CT provides pre-operative roadmap: Establish course of CN7 and status
of ossicular chain, oval window and inner ear before surgery.
EAC stenosis; tympanic plates present but hypoplastic
Example of Syndromic EAC Atresia:
Fanconi Anemia: EAC and Inner Ear Malformation
Left microtia (white arrow)
Distal turns of the cochlea are normal
Basal turn tapering of cochlea (arrows)
Bilateral EAC atresia (arrows)
V/S Normal
A metacarpal bone is missing in the thumbs
(white arrows)
Key Points in your report
CEMEM
1. EAC stenosis (small tympanic plate) vs atresia
2. Atresia plate thickness; bony vs membranous
3. Describe mastoid pneumatization
4. Middle ear space size; malformation
5. Erosive opacity c/w cholesteatoma
6. Ossicles: malformation, rotation, fusion
7. Oval window: stenosis or atresia
8. Facial nerve course, dehiscence
9. Inner ear anomalies
10. Mandibular condyle size/position
11. Zygomatic arch anomaly
12. Low placement of middle cranial fossa dura
END OF “EXTERNAL AUDITORY CANAL” SECTION
MIDDLE EAR
Case 1/3
Small rounded soft tissue mass medial to the ossicles
Hint
C O N G E N I TA L C H O L E S T E AT O M A
Best imaging tool:
T-bone CT
MR if large or recurrent or diagnosis uncertain
• Small, well-circumscribed soft tissue middle ear mass, medial to
ossicles with intact tympanic membrane, may erode ossicles and
other bony structures.
• MR: Peripheral enhancement, restricted diffusion.
Treatment: complete surgical resection.
MIDDLE EAR
Case 2/3
Axial
Coronal
Hint
Ossicular fixation:
head of the malleus to the roof of the middle ear
manubrium of the malleus to the lateral wall of the middle ear
C O N G E N I TA L O S S I C U L A R F I X AT I O N
Best imaging tool: High-resolution T-bone CT
• Congenital ankylosis: rigid bar or fibrous band connecting
ossicle to wall of MEC.
• Identify multiple fixations on CT.
Treatment: mechanical division or various types of laser
vaporization of bony ankylosis.
MIDDLE EAR
Case 3/3
Coronal
Ossification overlies oval window
Facial nerve overhangs the oval window
Axial
Hint
O VA L W I N D O W AT R E S I A
Best imaging tool: T-bone CT with coronal reconstruction
CT findings:
• Approximation of bone beneath lateral SCC with bone over cochlear
promontary
• Inferomedially or inferolaterally positioned tympanic segment of CN7
• Bilateral in 40%
Normal oval window
Treatment:
• Vestibulotomy with stapes prosthesis or total ossicular replacement
prothesis (TORP)
• CN7 ectopia is a relative surgical contraindication
Aberrant facial nerve canal
Oval window atresia
END OF “MIDDLE EAR” SECTION
INNER EAR
Case 1/10
Axial
Coronal
Complete absence of the cochlea
Cystic space representing the right vestibule and lateral SCC
Rudimentary superior SCC
Hint
COCHLEAR APLASIA
Best imaging tool: T-bone CT or MR
• No cochlea seen on CT or T2 MR but rest of membranous labyrinth
is present (with variable abnormalities)
• Usually bilateral
Treatment:
• Brainstem implantation if bilateral
• Cochlear implant contraindicated
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Case 1/10 continued: Contralateral side
Axial
Coronal
V/S Normal
Complete labyrinthine aplasia
LABYRINTHINE APLASIA
Best imaging tool: T-bone CT or MR
• Absent/hypoplastic otic capsule bone
• Absent cochlea, vestibule and SCC
• Often asymmetric: contralateral common
hypoplasia or cochlear IP-I anomaly
Treatment:
• Brainstem implantation if bilateral
• Cochlear implant contraindicated
cavity,
inner
ear
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INNER EAR
Case 2/10
Cystic Cochlea with an absent interscalar septum and modiolus
Dilated Vestibule
Hint
C O C H L E A R I N C O M P L E T E PA R T I T I O N T Y P E 1 ( I P - I )
Best imaging tool: MR 3D T2 weighted sequence (Fiesta/CISS/Space)
to identify CN8 components.
• Absent interscalar septum and modiolus, dilated SCC
→ Cystic Cochleovestibular Malformation (figure of 8)
• CN8 : Hypoplastic or absent
Treatment:
• None if contralateral ear is normal.
• Cochlear implantation if cochlear nerve present
• May be at risk of CSF gusher/perilymph leak
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INNER EAR
Case 3/10
Absent Interscalar septum between plump middle & apical turns (
)
Smooth external contour between middle & apical turns posterolaterally ("baseball cap" cochlea)
Hint
What is the frequently associated
finding?
Bilateral IP-II with modiolar
deficiency
+
Large right vestibular aqueduct
Axial
Hint
Sagittal Oblique
C O C H L E A R I N C O M P L E T E PA R T I T I O N T Y P E 2 ( I P - I I )
Best imaging tool: T-bone CT and MR (3D T2)
• Cochlea:
• Absent interscalar septum between middle and apical turns
(« Baseball cap » cochlea)
• Deficient or absent modiolus
• Usually associated with large vestibular aqueduct/large
endolymphatic sac/duct:
• ≥ 1 mm at midpoint
• ≥ 2 mm at operculum
Treatment:
• Avoid contact sports and prevent head trauma
• Cochlear implantation if profound bilateral SNHL
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INNER EAR
Companion case: Case 4/10
Hypothyroidism
and Goiter
Bilateral IP-II (
) and Large Vestibular Aqueducts (
)
Additional
history
PENDRED SYNDROME
Autosomal recessive
• Thyroid organification defect
• SNHL (fluctuating/progressive): LVA +/- IP-II
• SLC26A4 mutation
Treatment: Cochlear implantation for profound bilateral SNHL
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INNER EAR
Case 5/10
Normal Right side
Stenotic cochlear nerve canal and thickened
modiolus
Hint
COCHLEAR NERVE CANAL APLASIA
Best imaging tool: Axial and sagittal oblique 3D T2 weighted
sequence
Normal
Hypoplasia
Atresia
• Cochlea nerve canal stenosis < 1.7 mm.
Diameter is measured at its narrowest point.
Treatment:
• Brainstem implantation if CN absent
• Cochlear implantation (CI) relatively contraindicated
• However, may have some function with CI if some nerve
fibers are present
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INNER EAR
Case 6/10
Axial
Sagittal Oblique through the left IAC
Sagittal Oblique through the right IAC
Compared to the contralateral side, the left side shows an
absent cochlear nerve (
)
The right side is normal and shows an anterosuperior facial nerve,
an anteroinferior cochlear nerve and posterior superior and inferior
vestibular nerves
Hint
COCHLEAR NERVE APLASIA
Best imaging tool: Axial and sagittal oblique 3D T2 weighted
sequence
• Cochlear Nerve Deficiency: Cochlear nerve smaller than
normal CN7 (hypoplasia) or absent (aplasia).
Treatment:
• Brainstem implantation
• Cochlear implantation contraindicated
Springer Science and Business Media ©
INNER EAR
Case 7/10
Bilateral flattened cochlea (
)
Short and thick posterior semicircular canal (
)
Pigmentary anomalies:
• Blue eyes
• White hair
Hirschsprung
Hint
WAAR D EN BU R G SYN D R OME type IV
•
•
•
•
•
SCC: Shortened, thick posterior SCC
Vestibule and VA: Normal or enlarged
Cochlear: Normal or flattened
Cochlear nerve: Normal or absent
Brain: +/- Abnormal myelination
Waardenburg syndromes: Variable pigmentary anomalies,
SNHL, variable dystopia canthorum, upper limb anomalies,
Hirschsprung disease (type IV), peripheral neuropathy,
ataxia…
WAAR D EN BU R G SYN D R OME
Best imaging tool: MR 3D T2 weighted
(Fiesta/CISS/Space) to identify CN8 components.
sequence
Treatment: Cochlear implantation if cochlear nerve present
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INNER EAR
Case 8/10
Dilated IAC (
)
Widened cochlear apertures (
)
Dysmorphic cochlea with a “corkscrew appearance” (
Hint
)
X - L I N K E D S TA P E S G U S H E R
Best imaging tool: T-bone CT and MR
•
•
•
•
Cochlea: « Corkscrew » appearance
Cochlear nerve canal: Widened
IAC: Bulbous dilatation
Facial nerve canal: Wide labyrinthine and proximal tympanic
segments
• Dilated lateral SCCs
Treatment: Cochlear implantation with risk of CSF gusher and
meningitis
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INNER EAR
Case 9/10
Coloboma (
)
Cochlear malformation (
)
Small vestibules, absent SCC (
Absent olfactory nerve on the
right, small on the left
)
Hypoplastic clivus, basilar
invagination, small pons, inferior
vermian hypoplasia, small pituitary
Hint
Choanal atresia
Hypoplastic CN 7, 8 (
)
Right trigeminal artery (
)
CHARGE SYNDROME
Coloboma
Heart anomaly
Atresia choanae
Retardation: mental & somatic
Genital Hypoplasia
Ear abnormalities
CHARGE SYNDROME
Imaging:
• Choanal atresia, coloboma, cleft lip/palate
• Hypoplastic vestibule & hypoplastic/absent SCC
• Funnel shaped enlarged vestibular aqueduct
• Ossicular anomalies
• Thickened modioli, stenotic/absent cochlear nerve canals
• Flattened or absent apical and middle cochlear turns
• Stenotic/atretic oval windows & overlying anomalous
tympanic segments of CN7
• Large emissary veins, stenotic jugular foramina, hypoplasia
basiocciput, basilar invagination, & spinal anomalies
• Hypoplastic pons, cerebellar malformation
• CN hypoplasia/aplasia (mainly CN 1, 7 & 8)
CHARGE SYNDROME
Best imaging tool: MR 3D T2 weighted
(Fiesta/CISS/Space) to identify CN8 components.
sequence
Treatment: Cochlear implantation if cochlear nerve present
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INNER EAR
Case 10/10
Tapered basal turn of the cochlea (
)+
unwound/offset, hypoplastic middle & apical turns
Fusion of malformed ossicles to the attic bilaterally
Malformed posterior semicircular canals
Funnel shaped enlargement of Vestibular
Aqueducts bilaterally
Bilateral microtia with bilateral atresia of
the external auditory canals
Type 1 branchial cleft cyst
Renal cysts
BRANCHIO-OTO-RENAL SYNDROME
Autosomal dominant
Deafness + Branchial cleft cyst/fistula + Ear anomalies + Renal
anomalies (cysts, dysplasia, agenesis)
EYA1 gene mutation
Best imaging tool: T-bone CT
• Dilated eustachian tubes
• EAC: stenosis/atresia
• Middle ear: dysmorphic/fused ossicles
• Cochlea: Tapered basal turn, hypoplastic, offset middle/apical
turn → unwound appearance
• SCC anomaly
• Dilated, bulbous VA
• Flared IAC
• Anomalous CN7 canal
Treatment: Cochlear implantation for profound bilateral SNHL
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END OF “INNER EAR” SECTION
C E R E B E L L O P O N T I N E A N G L E – B R A I N PA R E N C H Y M A
Case 1/2
T2
T1+C
FLAIR
Nonenhancing mass within
the left CP angle presenting
restricted diffusion
DWI
ADC
CEREBELLOPONTINE ANGLE EPIDERMOID CYST
Best imaging tool: MR
MR findings:
• CPA cisternal insinuating mass
• Iso or slightly hyperintense on T1 and T2
• Does not attenuate on FLAIR
• Restricted diffusion
• Although congenital, it usually presents in adult life.
Treatment: Complete surgical resection
DWI MR to diagnose recurrences
C E R E B E L L O P O N T I N E A N G L E – B R A I N PA R E N C H Y M A
Case 2/2
Normal Temporal bone CT
Periventricular calcifications
Thick cortex. Further evaluation with an MRI of the brain was recommended.
MRI was performed
Sag T1
Ax T2
Cor T2 Fatsat
MRI demonstrates diffuse bilateral polymicrogyria in the frontal lobes, along the sylvian fissures and in the parietal and temporal lobes.
The polymicrogyria and the periventricular calcifications are in favor of a diagnosis of congenital CMV infection as the cause of congenital SNHL
CMV INFECTION
CT:
• Intracranial calcifications: in germinal matrix, periventricular regions and basal ganglia
• White matter low density regions
• Ventriculomegaly/cerebral atrophy/destructive encephalopathy
• Neuronal migration disorders
MR:
• Microcephaly
• Migrational abnormalities : polymicrogyria
• White matter lesions
• Ventriculomegaly and subarachnoid space enlargement
• Periventricular and temporal pole cysts
• Delayed myelination
E N D O F “ C E R E B E L L O P O N T I N E A N G L E – B R A I N PA R E N C H Y M A ” S E C T I O N
SUMMARY
• A patterned approach to reading a temporal bone CT for CHL simplifies
the radiological diagnosis of complex pathology.
• MR imaging is preferred in cases where lesions in the inner ear, cranial
nerves or brain are suspected (sensorineural hearing loss).
• Cochlear aplasia, cochlear nerve aplasia and cochlear nerve aperture
aplasia should be identified, as they constitute absolute or relative
contraindications to cochlear implants.
• A relative contraindication to cochlear implantation is the risk of CSF
gusher from a dilated cochlear nerve aperture with absence of the
modiolus.
• Keep in mind that only 20 to 30% of CHL will present anomalies on
imaging, since hearing loss is frequently due to isolated abnormalities on
a cellular or microscopic level.
REFERENCES
• Robson, Koch, Harnsberger. Specialty Imaging, Temporal Bone. Amirsys
• B.Y. Huang, C. Zdanski, and M. Castillo. Pediatric Sensorineural Hearing Loss, Part
1: Practical Aspects for Neuroradiologists. AJNR Am J Neuroradiol;2012 33: 211217
• B.Y. Huang, C. Zdanski, and M. Castillo. Pediatric Sensorineural Hearing Loss, Part
2: Syndromic and Acquired Causes. AJNR Am J Neuroradiol 2012;33: 399-406
• Robson CD. Congenital hearing impairment. Pediatr Radiol. 2006;Apr;36(4):309-24.
• Billings KR, Kenna MA. Causes of pediatric sensorineural hearing loss: yesterday
and today. Arch Otolaryngol Head Neck Surg 1999;125:517