Imaging of hearing loss: Sensorineural hearing loss

What’s essential…what’s new

felice.d’arco@gosh.nhs.uk

Summary

Radiological anatomy of the ear

Inner ear malformations: the essential

Inner ear malformation: new insights

Syndromic associations

Acquired causes

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Complementary role of MRI

Ant

Sup

Case courtesy of Rishi Agrawal, Radiopaedia.org

Classification of Inner Ear Malformations

Joshi et al. 2012

No pathophysological correlation (only timing of arrest)

Only one type of cochlear hypoplasia

Only two type of Incomplete partition

Sennaroglu L 2016

http://radiologykey.com/

Complete Labyrinthine Aplasia (Michel Deformity)

Joshi et al. 2012

Ozgen et al. 2009

Rudimentary otocyst

Between 3rd and 4th week the inner ear is in form of an otocyst

Millimetric round-shaped cyst in the otic capusle

Absent or small IAC ABI is the only therapy

Sennaroglu 2016

Common Cavity

Unique cavity before differentiation into cochlea and vestibule (4th week)

IAC present (narrow or normal) CN present (often hypoplastic) Possible Cochlear implantation

R L

R L

CN 7 CN 7

CN 8

Cochlear aplasia

Cochlear hypoplasias

“Clear and definite formation of a cochlea whose external

dimensions are less than those of a normal cochlea.”

Incomplete Partition Anomalies

“Cochlea with internal architecture abnormalities

(i.e. modiolus, ISS).”

• Are cochleas with abnormal internal structure of normal or small size?

• Do hypoplastic cochleas always have an abnormal internal structure?

Gulya and Schuknecht 2007; Erixon 2009 ; Sennaroglu 2016

•CH I and CH II are smaller versions of a cochlea with incomplete partition •CH-III and CH-IV are smaller versions of a normal partitioned cochlea.

“Because of the resolution of CT the modiolar defects may be not identified”

Relatively high percentage of CH among inner ear malformations: 18/33 (Sennaroglu 2016)

Possible usefulness of standardized measurements

Cochlear hypoplasia type 3

To the best of our knowledge …

- Purcell et al. Head Neck Surg 2003;128:78-87

- Purcell et al. Laryngoscope: 2003;113:1908-11

-Probst et al. Laryngoscope 2005;115:1865-62

-Purcell et al. Laryngoscope 2006;116:1439-46

-Shim et al. Otology and Neurotology 2006;27:831-37

-Blaser et al. Laryngoscope 2006; 116;2113-9

-Vijayasekaran et al. AJNR 2007;28:1133-38

-Chen et al. Arch Otol Laryngol Head Neck Surgery 2008;134:50-6

-Probst et al.Laryngoscope 2008;118:517-21

-Zhou et al. Otol Neurotol 2009;30:184-6

-Lan et al. Eur Arch Otorhinolarynghol 2009;266:1361-4

-Teissier et al. Pediatric Radiol 2010;40:275-83

-Pakdaman et al. Cochlear Implatns Int 2011;12:54-7

-Saliba et al. Laryngoscope 2014;124 :E141-7

Cochlear height : n.v. > 4.5 mm

Maximal height measured perpendicular to the plane of the the oval window

-Shim et al. Otology and Neurotology 2006;27:831-37

-Purcell et al. Laryngoscope: 2003;113:1908-11

Clinical implication

• Different prognoses depending on the type of malformation (cochlear hypoplasia: lower level of speech performance)

• Appropriate electrode choice may influence the result of CI in cochlear hypoplasia

• Electrode thin (<0.8 mm) and short (< 20 mm)

Buchman et al. Cochlear Implantation in Children with Congenital Inner Ear Malformations. Laryngoscope 2004

ax

21 month-old, female: Profound bilateral SNHL

parasag

Incomplete Partition Type 1

- Radiographics 2012; 32 (3), 683-698 - Cochlear Implants International 2016; 17 (1), 1-20

5 year-old: Profound bilateral SNHL

Incomplete Partition Type 2 + dilated vastibule + EVA (Mondini

triad)

Normal

Incomplete Partition type 2

Association with EVA and Dilated vestibule

Dilatation of the Scala Vestibuli Possible aetiology: High CSF pressure

transmitted to the cochlea Partial abnormality of the internal

cochlear structure Syndromic association

Incomplete Partition type 2: mild spectrum

Normal

1 year-old male: progressive mixed hearing loss Incomplete Partition type 3

- X-linked deafness: POU3F4 gene mutation

- Progressive mixed hearing loss

- Interscalar septa present, modiolus absent

- No bony partition between the fundus and

the basal turn of the cochlea

- Dilated IAC

- High risk of gushing during stapes

manipulation

Incomplete Partition type 3

Incomplete Partition type 3: etiopathogenesis

normal

Otic capsule is thinner in X-linked deafness if compared with normal

In normal subject the endosteal layer of otic capsule follow the cochlear profile

Enchodral and pariosteal layers determine the increase of the thickness of the OC

IP-III: otic capsule thinner and follow the profile of the cochlea (normal ISS)

Enchodral and pariosteal layers absent/hypodeveloped

Endosteal layer vascular supply from the middle ear mucosa

Dysplastic SCCs : bony island < 3 mm

-Blaser et al. Laryngoscope 2006; 116;2113-9

Persistent lateral semicircular canal anlage

Cochlear nerve deficiency (CND)

R

L

CN7

CN8

Syndromic Causes of SNHL Presence of other distinctive clinical features in addition to hearing loss

300 syndromic forms of hearing loss have been described

Sometimes SNHL is not reason for imaging

Important: BOR, CHARGE, Apert syndrome, Alagille syndrome, Down

syndrome, Pendred syndrome , Waardenburg Syndrome, X-linked

deafness.

Important to recognize constellation of findings or to look at the inner

ears in case of known association (e.g. Down)

-Huang et al. AJNR 2012

control DS

Lateral SCC bony island Cut-off: 3 mm

Down syndrome

-Blaser et al. Laryngoscope 2006; 116;2113-9

Branchio-oto-renal syndrome • autosomal dominant

• hearing loss + auricular malformations + branchial arch closure defects + renal anomalies.

• Findings in the ears: Cochlear hypoplasia + abnormal ossicles + other

CHARGE Syndrome

• Coloboma

• Heart defects

• Atresia of the choanae

• Retarded growth development

• Genital hypoplasia

• Ear anomalies

• Others: rhombencephalic dysfunction, cranial neuropathies, and dysfunction of the hypothalamic-hypophyseal axis

• Middle + inner ears malformations

CHARGE Syndrome

pt1

pt2

Pendred Syndrome • Most common syndromic deafness

• Severe bilateral SNHL + euthyroid goiter

• Bilateral Mondini triad

Waardenburg Syndrome • Pigmentation changes + deafness

• Several genes: SOX 10 Hirschsprung disease + Kalmann

• Typical cochlea hypoplasia

Acquired Causes of SNHL: 4 y, Bilateral SNHL following meningitis

Typical Labyrinthitis Ossificans !

Labyrinthitis

• Inflammatory process of the membranous labyrinth

• Acute SNHL and vertigo

• Meningitis +++

• Rarely non-infectious: trauma, autoimmune, toxic

• 3 radiological stages:

– Acute : CT normal / enhancement on MRI

– Firbrous (2 weeks): CT normal/ CISS images is seen as loss of the normal fluid signal and contrast

– Labyrinthitis ossificans: osteoplastic bone formation visible in CT and MRI (difficult Cochlear implantation)

-Huang et al. AJNR 2012

NF2: multiple meningiomas, schwannomas (+++ CN VIII) and spinal ependymomas

Take home messages New classification of IEMs based on histology clinical

correlation

MRI more sensitive and specific than CT for inner ear

IAMs are a spectrum of malformations (subtle findings !!! )

Usefulness of measurements

Look for syndromic associations

Acquired causes of earing loss need to be evaluated in the

clinical context

References • Pediatric sensorineural hearing loss, part 1: Practical aspects for

neuroradiologists. Huang BY, Zdanski C, Castillo M. AJNR Am J Neuroradiol.

2012 Feb;33(2):211-7

• Pediatric sensorineural hearing loss, part 2: Practical aspects for

neuroradiologists. Huang BY, Zdanski C, Castillo M. AJNR Am J Neuroradiol.

2012 Feb;33(3):399-406

• CT and MR imaging of the inner ear and brain in children with congenital

sensorineural hearing loss. Joshi VM1, Navlekar SK, Kishore GR, Reddy KJ,

Kumar EC. Radiographics. 2012 May-Jun;32(3):683-98

• Histopathology of inner ear malformations: Do we have enough evidence to

explain pathophysiology? Sennaroglu L. Cochlear Implants Int. 2016;17(1):3-20

felice.d’arco@gosh.nhs.uk