title: High-resolution magnetic resonance imaging of the temporomandibular joint: image quality at 1.5 and 3.0 Tesla in volunteers.
abstract: OBJECTIVE
  To assess the image quality of a high-resolution imaging protocol for the temporomandibular joint (TMJ) at 3.0 T and to compare it with our standard 1.5 T protocol.
  
  
  METHODS
  Fifteen volunteers without history of TMJ dysfunction underwent bilateral magnetic resonance imaging (MRI) of the TMJ with the jaw in closed and open position. MRI was performed with using a 1.5 T (standard TMJ coil) and 3.0 T (purpose build phased array coil) MR system (Gyroscan Intera 1.5 T and 3.0 T; Philips Medical Systems, Best, the Netherlands). Imaging protocols consisted of a parasagittal PDw-TSE sequence and a coronal PDw-TSE sequence in closed mouth position and a sagittal PDw-TSE sequence in open mouth position. Acquisition parameters were adjusted for 3.0 T and voxel size was reduced from 0.29 x 0.29 x 3.0 mm (1.5 T) to 0.15 x 0.15 x 1.5 mm (3.0 T). Total examination time (15 minutes) was similar for both systems. Two observers assessed in consensus delineation, image quality, and artifacts of anatomic landmarks (disk, bilaminar zone, capsular attachment, cortical bone) and ranked them qualitatively on a 5-point scale from 1 (optimal) to 5 (nondiagnostic). Disk position and motility was noted. For CNR analysis, signal intensity from disk and retrodiscal tissue was measured.
  
  
  RESULTS
  Disk position and mobility was identical at both field strengths. All anatomic landmarks were visualized significantly better at 3.0 T. In particular, the capsular attachment was depicted in more detail. Overall image quality was ranked significantly higher at 3.0 T, whereas artifact score was similar. Quantitative evaluation showed significantly higher CNR for 3.0 T (10.23 vs. 8.08, P < 0.0001).
  
  
  CONCLUSIONS
  Depiction of the normal anatomy of the TMJ benefits significantly when investing the higher SNR at 3.0 T into better spatial resolution. We anticipate that this advantage of 3.0 T MRI will also permit a more detailed analysis of capsular and disk pathology.
authors.affiliation: Department of Clinical Radiology, University of Muenster, Münster, Germany. stehlin@uni-muenster.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Stehling
authors.forename: Volker
authors.initials: V
authors.lastname: Vieth
authors.forename: Rainald
authors.initials: R
authors.lastname: Bachmann
authors.forename: Isabelle
authors.initials: I
authors.lastname: Nassenstein
authors.forename: Harald
authors.initials: H
authors.lastname: Kugel
authors.forename: Hendrik
authors.initials: H
authors.lastname: Kooijman
authors.forename: Walter
authors.initials: W
authors.lastname: Heindel
authors.forename: Roman
authors.initials: R
authors.lastname: Fischbach
mesh_terms: D000328:Adult; D016477:Artifacts; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018709:Statistics, Nonparametric; D013704:Temporomandibular Joint / Q000033:anatomy & histology*