title: Potential of fluid-attenuated inversion recovery (FLAIR) in identification of temporomandibular joint effusion compared with T2-weighted images.
abstract: OBJECTIVE
  The purpose of this study was to determine the potential of fluid-attenuated inversion recovery (FLAIR) sequence images in the identification of joint effusion (JE) compared with T2-weighted images.
  
  
  METHODS
  A total of 31 joints (28 patients) with JE were investigated by magnetic resonance imaging (MRI). Regions of interest were placed over JE, cerebrospinal fluid (CSF), and gray matter (GM) on T2-weighted and FLAIR images and their signal intensities compared. The signal intensity ratios (SIRs) of JE and CSF were calculated with GM as the reference point. The Pearson product-moment correlation coefficient was used for the statistical analysis.
  
  
  RESULTS
  The SIR of JE showed a strong correlation between T2-weighted and FLAIR images. However, no correlation was observed for CSF. The average suppression ratio for JE was lower than that for CSF.
  
  
  CONCLUSIONS
  MRI using FLAIR sequences revealed that JE was not just water content, but a fluid accumulation containing elements such as protein. Further studies are needed, and FLAIR sequences could be useful for the diagnosis of pain and symptoms of the temporomandibular joint (TMJ).
authors.affiliation: Oral Health Science Center HRC7, Tokyo Dental College, Mihama-ku, Chiba, Japan. imotokenichi@tdc.ac.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Imoto
authors.forename: Mika
authors.initials: M
authors.lastname: Otonari-Yamamoto
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sano
authors.forename: Aya
authors.initials: A
authors.lastname: Yamamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000033:anatomy & histology; D002555:Cerebrospinal Fluid; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D016247:Information Storage and Retrieval; D004204:Joint Dislocations / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008335:Mandibular Condyle / Q000473:pathology; D008875:Middle Aged; D011506:Proteins / Q000737:chemistry; D012189:Retrospective Studies; D013582:Synovial Fluid / Q000737:chemistry; D019224:Temporomandibular Joint Disc / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D011506:Proteins