This document summarizes recent insights into inner ear malformations. It begins with an overview of the radiological anatomy of the inner ear and classifications of inner ear malformations. It then discusses specific types of malformations like incomplete partition, cochlear hypoplasia, and common cavity in more detail. The document also reviews syndromic associations of inner ear malformations and acquired causes of sensorineural hearing loss. Key points emphasized include the spectrum of subtle findings for inner ear malformations, the importance of standardized measurements and recognizing syndromic associations, and the usefulness of MRI over CT for evaluation.

1. What’s essential…what’s new
felice.d’arco@gosh.nhs.uk

2. Summary
Radiological anatomy of the ear
Inner ear malformations: the essential
Inner ear malformation: new insights
Syndromic associations
Acquired causes

3. http://radiologykey.com/

4. http://www.radiologyassistant.nl/enhttp://audilab.bmed.mcgill.ca

5. http://www.radiologyassistant.nl/enhttp://audilab.bmed.mcgill.ca

6. http://www.radiologyassistant.nl/enhttp://audilab.bmed.mcgill.ca

7. http://www.radiologyassistant.nl/enhttp://audilab.bmed.mcgill.ca

8. http://www.radiologyassistant.nl/enhttp://audilab.bmed.mcgill.ca

9. http://www.radiologyassistant.nl/enhttp://audilab.bmed.mcgill.ca

10. http://www.radiologyassistant.nl/enhttp://audilab.bmed.mcgill.ca

11. Complementary role of MRI

12. Ant
Sup
Case courtesy of Rishi Agrawal, Radiopaedia.org

13. 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

14. http://radiologykey.com/

15. Complete Labyrinthine Aplasia (Michel Deformity)
Joshi et al. 2012
Ozgen et al. 2009

16. 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

17. RL
RL
CN 7
CN 7
CN 8

19. Cochlear aplasia

20. 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?

21. 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.

22. “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

23. 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

24. 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

25. 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

26. ax
21 month-old, female: Profound bilateral SNHL
parasag
Incomplete Partition
Type 1

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

28. 5 year-old: Profound bilateral SNHL
Incomplete Partition Type 2 +
dilated vastibule + EVA (Mondini
triad)

30. Normal

31. 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

32. Incomplete Partition type 2: mild spectrum
Normal

33. 1 year-old male: progressive mixed hearing loss Incomplete Partition type 3

34. - 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

35. 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

36. Dysplastic SCCs : bony island < 3 mm
-Blaser et al. Laryngoscope 2006; 116;2113-9
Persistent lateral semicircular canal anlage

37. Cochlear nerve deficiency (CND)
R
L
CN7
CN8

38. 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

39. control DS
Lateral SCC bony island Cut-off:
3 mm
Down syndrome
-Blaser et al. Laryngoscope 2006; 116;2113-9

40. 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

41. 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

42. CHARGE Syndrome
pt1
pt2

43. Pendred Syndrome
• Most common syndromic deafness
• Severe bilateral SNHL + euthyroid goiter
• Bilateral Mondini triad

44. Waardenburg Syndrome
• Pigmentation changes + deafness
• Several genes: SOX 10  Hirschsprung disease + Kalmann
• Typical cochlea hypoplasia

45. Acquired Causes of SNHL: 4 y, Bilateral SNHL following meningitis
Typical Labyrinthitis Ossificans !

48. 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

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

50. 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

51. 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

52. felice.d’arco@gosh.nhs.uk