Disk displacement of the temporomandibular joint: sonography versus MR imaging.

OBJECTIVE: The purpose of this study was to determine the value of dynamic sonography in the evaluation of internal derangements of a temporomandibular joint (TMJ) during maximal mandibular range of motion.

SUBJECTS AND METHODS: Maximal mandibular range of motion was performed during high-resolution sonography of the TMJ in 64 consecutive patients (128 joints; nine males and 55 females; age range, 17-65 years; mean age, 35 years 6 months), all of whom subsequently underwent MR imaging. MR imaging confirmed disk displacement with reduction in 27 joints and disk displacement without reduction in 60 joints of the 128 examined. The high-resolution sonography and MR imaging findings for these 27 and 60 TMJs, respectively, were analyzed.

RESULTS: Dynamic high-resolution sonography performed during the maximal range of motion helped to detect 81 instances (93%) of internal derangement, 22 instances (82%) of disk displacement with reduction, and 50 instances (83%) of disk displacement without reduction. There was one false-positive finding for internal derangement. The accuracy of prospective interpretation of high-resolution sonograms of internal derangement, disk displacement with reduction, and disk displacement without reduction was 95%, 92%, and 90%, respectively.

CONCLUSION: When real-time images are interpreted by expert radiologists, dynamic sonography performed during maximal mandibular range of motion may provide valuable information about disk displacement of the TMJ.