title: Diagnosis of retrodiscal tissue in painful temporomandibular joint (TMJ) by fluid-attenuated inversion recovery (FLAIR) signal intensity.
abstract: OBJECTIVE
  The purpose of the present study is to analyze the fluid-attenuated inversion recovery (FLAIR) signal intensity of the retrodiscal tissue in a painful temporomandibular joint (TMJ), and to develop a diagnostic system based on FLAIR data.
  
  
  METHODS
  The study was based on 33 joints of 17 patients referred for MR imaging of the TMJ. Regions of interest were placed over retrodiscal tissue and gray matter (GM) on FLAIR images. Using signal intensities of GM as reference points, signal intensity ratios (SIR) of retrodiscal tissue were calculated. SIRs in painful TMJ were compared with those in painless TMJ. Wilcoxon's Rank Sum Test was used to analyze the difference in SIRs between the painful and painless groups (P<0·05).
  
  
  RESULTS
  The SIRs of retrodiscal tissue were significantly higher in painful joints than in painless joints.
  
  
  CONCLUSIONS
  FLAIR sequences provide a high signal in patients having painful TMJ, and it suggests that retrodiscal tissue in painful TMJ contains elements such as protein.
authors.affiliation: Division of Radiology, Department of Oral Diagnostic Sciences, Showa University School of Dentistry , Tokyo, Japan.
authors.forename: Migiwa
authors.initials: M
authors.lastname: Kuroda
authors.forename: Mika
authors.initials: M
authors.lastname: Otonari-Yamamoto
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sano
authors.forename: Mamiko
authors.initials: M
authors.lastname: Fujikura
authors.forename: Mamoru
authors.initials: M
authors.lastname: Wakoh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005157:Facial Pain / Q000175:diagnosis; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008409:Mastication / Q000502:physiology; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D016059:Range of Motion, Articular / Q000502:physiology; D013704:Temporomandibular Joint / Q000473:pathology*; D019224:Temporomandibular Joint Disc / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis*; D055815:Young Adult
keywords: Fluid-attenuated inversion recovery (FLAIR) image; MR sequence; Retrodiscal tissue; Signal intensity; Temporomandibular joint (TMJ)