title: Depicting the semicircular canals with inner-ear MRI: a comparison of the SPACE and TrueFISP sequences.
abstract: OBJECTIVE
  To assess the ability of magnetic resonance imaging (MRI) to depict the semicircular canals of the inner ear by comparing results from the sampling perfection with application-optimized contrasts by using different flip angle evolutions (SPACE) sequence with those from the true free induction with steady precession (TrueFISP) sequence.
  
  
  METHODS
  A 1.5-T MRI system was used to perform an in vivo study of 10 healthy volunteers and 17 patients. A three-point visual score was employed for assessing the depiction of the semicircular canals and facial and vestibulocochlear nerves and the contrast-to-noise ratio (CNR) was computed for the vestibule and pons on images with the SPACE and TrueFIPS sequences.
  
  
  RESULTS
  There were no susceptibility artifact-related filling defects with the SPACE sequence. However, the TrueFISP sequence showed filling defects for at least one semicircular canal on both sides in seven cases for healthy subjects and in 10 cases for patients. The CNR with the SPACE sequence was significantly higher than with the TrueFISP sequence (P < 0.05). There was no statistically significant difference in depicting the facial and the vestibulocochlear nerves (P = 0.32).
  
  
  CONCLUSIONS
  For the depiction of the semicircular canal, the SPACE sequence is superior to the TrueFISP sequence.
authors.affiliation: Department of Radiology, Tokyo Women's Medical University Medical Center East, Tokyo, Japan. yancy123xyz@nifty.com
authors.forename: Shinya
authors.initials: S
authors.lastname: Kojima
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Masami
authors.initials: M
authors.lastname: Hirata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shinohara
authors.forename: Eiko
authors.initials: E
authors.lastname: Ueno
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D007758:Ear, Inner / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012665:Semicircular Canals / Q000473:pathology*; D000159:Vestibulocochlear Nerve / Q000473:pathology; D055815:Young Adult