Magnetic resonance imaging of the temporomandibular joint. Increased T2 signal in the retrodiskal tissue of painful joints.

The cause of pain associated with TMJ disk displacement and internal derangement is unclear. In clinical work with MR imaging we have noted increased T2 signal from the retrodiskal tissue in some patients with TMJ pain and dysfunction. The purpose of this study was to analyze a possible association between pain and the T2 signal intensity from the retrodiskal tissue on MR images. The study was based on 48 joints in 33 patients referred for MR imaging of the TMJ. The T2 signal from the retrodiskal tissue was measured on the MR scanner and was correlated to the degree of pain. The results showed a statistically significant (p < 0.05) association between pain and increased T2 weighted signal. The T2 signal intensity ranged between 251 and 478 and was highest in the painful joints and lowest in the joints without pain. We conclude that the average T2 signal from the retrodiskal tissue is higher in painful joints than in nonpainful joints. This might reflect an increased vascularity of the joint tissue.