title: Improved imaging of cochlear nerve hypoplasia using a 3-Tesla variable flip-angle turbo spin-echo sequence and a 7-cm surface coil.
abstract: OBJECTIVE
  Magnetic resonance imaging of the temporal bone has an important role in decision making with regard to cochlea implantation, especially in children with cochlear nerve deficiency. The purpose of this study was to evaluate the usefulness of the combination of an advanced high-resolution T2-weighted sequence with a surface coil in a 3-Tesla magnetic resonance imaging scanner in cases of suspected cochlear nerve aplasia.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Seven patients with cochlear nerve hypoplasia or aplasia were prospectively examined using a high-resolution three-dimensional variable flip-angle turbo spin-echo sequence using a surface coil, and the images were compared with the same sequence in standard resolution using a standard head coil. Three neuroradiologists evaluated the magnetic resonance images independently, rating the visibility of the nerves in diagnosing hypoplasia or aplasia.
  
  
  RESULTS
  Eight ears in seven patients with hypoplasia or aplasia of the cochlear nerve were examined. The average age was 2.7 years (range, 9 months-5 years). Seven ears had accompanying malformations. The inter-rater reliability in diagnosing hypoplasia or aplasia was greater using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence (fixed-marginal kappa: 0.64) than with the same sequence in lower resolution (fixed-marginal kappa: 0.06).
  
  
  CONCLUSIONS
  Examining cases of suspected cochlear nerve aplasia using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence in combination with a surface coil shows significant improvement over standard methods.
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Hannover, Germany.
authors.forename: Anja M
authors.initials: AM
authors.lastname: Giesemann
authors.forename: Peter
authors.initials: P
authors.lastname: Raab
authors.forename: Stefan
authors.initials: S
authors.lastname: Lyutenski
authors.forename: Sabine
authors.initials: S
authors.lastname: Dettmer
authors.forename: Eva
authors.initials: E
authors.lastname: Bültmann
authors.forename: Cornelia
authors.initials: C
authors.lastname: Frömke
authors.forename: Thomas
authors.initials: T
authors.lastname: Lenarz
authors.forename: Heinrich
authors.initials: H
authors.lastname: Lanfermann
authors.forename: Friedrich
authors.initials: F
authors.lastname: Goetz
mesh_terms: D002675:Child, Preschool; D019929:Cochlear Implantation / Q000379:methods; D003056:Cochlear Nerve / Q000002:abnormalities*; D015331:Cohort Studies; D000013:Congenital Abnormalities / Q000473:pathology* / Q000601:surgery; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015588:Observer Variation; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D058996:Quality Improvement
keywords: 3 Tesla; Inner ear malformation; cochlear nerve aplasia; cochlear nerve hypoplasia; magnetic resonance imaging; temporal bone