Clinical significance of MR signal intensity of the temporomandibular joint meniscus

The center of the posterior band of the temporomandibular joint (TMJ) meniscus often shows a higher magnetic resonance (MR) signal intensity on spin-echo images than does its margins or the rest of the meniscus. This can give a distinctive appearance, providing useful anatomic landmarks. It is possible that the level of signal intensity in the meniscus can be used as a system to classify the severity and/or the duration of TMJ dysfunction. To test this hypothesis, 125 studies of symptomatic patients and 50 studies of asymptomatic volunteers were reviewed in conjunction with 1-3-year clinical follow-up (available for 80% of studies). Follow-up MR images were obtained when possible. To date, relatively poor correlation was seen between signal intensity and the severity or duration of pain, the duration of other symptoms, the degree of anterior displacement, or the progression of dysfunction since the initial study. Distortion of disk morphology showed better correlation with duration of symptoms. The degree of TMJ dysfunction as studied by MR imaging is best classified by the amount of displacement, effusion, reduction on full open view, and distortion of disk morphology and adjacent bone