A practical approach to interpretation of MRI of the temporomandibular joint

Temporomandibular disorders (TMDs) such as pain, joint sounds, and impaired movement are common, and magnetic resonance imaging (MRI) is now the method of choice for diagnostic assessment.

To describe MR criteria chosen and the amount of temporomandibular joint (TMJ) pathology registered when examining MR images from patients referred to a university hospital for imaging of their TMJs.

The TMJs of 152 consecutive patients, 102 women and 40 men, referred for MRI during an 18 month period were imaged with a 1.5 T imaging system. Twelve asymptomatic students, seven women and five men, gave informed consent and acted as a control group.

Moderate to extensive disk displacement was registered in 53% of the patients’ TMJs, and 38% of the disks were deformed. Degenerative changes registered were flattening of the condyle heads in 50% of the TMJs and erosion of their cortical surfaces in 30%. Osteophytes were present in 31% of the condyles and bone marrow edema in 30%. Marked to extensive effusion in synovial compartments was registered in 39% of the studied TMJs. In the control group, none of the TMJs showed anterior disk displacement, deformed disks or degenerative changes, but 8 of the 24 joints showed marked effusion. A tendency for a higher amount of disk displacement and deformation was seen among young age groups and more degenerative changes in older age groups, but differences among groups were not significant when tested with chi-square analysis.

Defined MR criteria that allow for comparative assessment are presented. According to these criteria, a large proportion of the patients referred for MR examination showed morphologic changes indicating TMJ pathology.