title: Preoperative detection of the facial nerve by high-field magnetic resonance imaging in patients with vestibular schwannoma.
abstract: BACKGROUND
  Preoperative knowledge of the position of the facial nerve relative to a vestibular schwannoma would be very helpful to decide for an adapted therapeutic strategy. The aim of this study is to assess the feasibility of predicting the course of the facial nerve in vestibular schwannoma patients using 3 T high-resolution magnetic resonance cisternography in a large consecutive series.
  
  
  METHODS
  The study was prospectively conducted in 82 patients operated for vestibular schwannoma. All patients underwent preoperative gadolinium (Gd)-enhanced, balanced fast-field echo (bFFE) imaging. The course of the facial nerve was estimated preoperatively and the results were verified with the intraoperative findings.
  
  
  RESULTS
  The facial nerve could be identified by preoperative MRI in 38 cases (46.3 %). In 28 cases (34.1 % of total patients, 73.7 % of identified patients), the course of the MRI-identified facial nerve was completely congruent with the intraoperative findings. In the patient group with MRI-identified facial nerves, tumor size was smaller and the number of solid type was larger. There were 23 cases where the tumor was solid and smaller than 20 mm. Nineteen (82.6 %) of those cases could estimate the facial nerve preoperatively and 16 cases (69.6 %) have complete congruency.
  
  
  CONCLUSIONS
  Gd-enhanced bFFE at 3 T is capable of demonstrating the location of the facial nerve in vestibular schwannoma patients prior to surgery. Slices that were perpendicular to the internal auditory canal were useful besides axial images. In small, solid-type tumors, facial nerve was more easily identified than other types of tumors.
authors: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan. tomoakin@med.kobe-u.ac.jp
authors: Tomoaki
authors: T
authors: Nakai
authors: Hirotaka
authors: H
authors: Yamamoto
authors: Kazuhiro
authors: K
authors: Tanaka
authors: Junji
authors: J
authors: Koyama
authors: Atsushi
authors: A
authors: Fujita
authors: Masaaki
authors: M
authors: Taniguchi
authors: Kohkichi
authors: K
authors: Hosoda
authors: Eiji
authors: E
authors: Kohmura
mesh_terms: D005154:Facial Nerve / Q000473:pathology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009464:Neuroma, Acoustic / Q000473:pathology* / Q000601:surgery*; D058958:Organs at Risk / Q000473:pathology*; D011300:Preoperative Care / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*