Imaging of hearing loss: Sensorineural hearing loss
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Transcript of Imaging of hearing loss: Sensorineural hearing loss
What’s essential…what’s new
felice.d’[email protected]
Summary
Radiological anatomy of the ear
Inner ear malformations: the essential
Inner ear malformation: new insights
Syndromic associations
Acquired causes
http://radiologykey.com/
http://www.radiologyassistant.nl/en http://audilab.bmed.mcgill.ca
http://www.radiologyassistant.nl/en http://audilab.bmed.mcgill.ca
http://www.radiologyassistant.nl/en http://audilab.bmed.mcgill.ca
http://www.radiologyassistant.nl/en http://audilab.bmed.mcgill.ca
http://www.radiologyassistant.nl/en http://audilab.bmed.mcgill.ca
http://www.radiologyassistant.nl/en http://audilab.bmed.mcgill.ca
http://www.radiologyassistant.nl/en http://audilab.bmed.mcgill.ca
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’[email protected]