title: Signal intensity on fluid-attenuated inversion recovery images of condylar marrow changes correspond with slight pain in patients with temporomandibular joint disorders.
abstract: OBJECTIVE
  Edema and necrosis of the temporomandibular joint (TMJ) have been described in terms of bone marrow signal abnormalities in magnetic resonance imaging (MRI). However, painful joints often show no such signaling abnormalities, making the diagnosis of TMJ disorders difficult in the clinical setting. An association has been suggested between TMJ bone marrow change and TMJ pain, but even when such change results in slight pain, it may be too slight to be visually apparent on MR images. We hypothesized that fluid-attenuated inversion recovery (FLAIR) can be used to detect such minimal changes. The purpose of this study was to determine whether there is an association between signal intensity on FLAIR images and pain in the TMJ.
  
  
  METHODS
  The study included 85 TMJs in 45 patients referred to our department for MRI. The signal intensity on FLAIR images was measured. Pain was evaluated based on the visual analog scale. An unpairedttest and Pearson's product-moment correlation coefficient were used for the statistical analysis. Apvalue of <0.05 was considered statistically significant.
  
  
  RESULTS
  Signal intensity on the FLAIR images was significantly higher in painful than in nonpainful TMJs, although a significant correlation was not observed between the signal intensity and the pain score.
  
  
  CONCLUSIONS
  The results of this study suggest an association between abnormalities in the marrow of the mandibular condyle and pain. They also indicate that FLAIR imaging is a useful tool in the clinical diagnosis of painful TMJs.
authors.affiliation: Department of Physiology, Tokyo Dental College, Misakichyo 2-1-14, Chiyoda-ku, Tokyo, 101-0061 Japan ; Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Kodama
authors.affiliation: Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Otonari-Yamamoto
authors.affiliation: Division of Radiology, Department of Oral Diagnostic Sciences, Showa University School of Dentistry, Tokyo, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sano
authors.affiliation: Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Junichirou
authors.initials: J
authors.lastname: Sakamoto
authors.affiliation: Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Imoto
authors.affiliation: Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Wakoh
keywords: Bone marrow; Fluid-attenuated inversion recovery (FLAIR); Magnetic resonance imaging (MRI); Temporomandibular joint (TMJ)