MRI scoring system for inflammatory activity and osseous deformity of TMJ.
| Grade | Inflammatory Activity | Grade | Osseous Deformity |
|---|---|---|---|
| Normal | 0 ≤ small amount of joint fluid, enhancement confined to joint fluid | Normal | 0 S-shaped articular eminence/glenoid fossa, round (young patients) or squared (older patients) mandibular condyle |
| Mild | 1 Enhancement exceeding visible joint fluid, ± bone marrow edema | Mild | 1 Mild flattening of condyle, mild flattening of articular eminence/glenoid fossa |
| Moderate | 2 Intense enhancement involving entire joint space, ± enhancing joint effusion ± bone marrow edema | Moderate | 2 Moderate flattening of condyle, moderate flattening of articular eminence/glenoid fossa, ± small erosions |
| Severe | 3 Grade 2 plus visible synovial thickening with intermediate signal intensity on T2-weighted image | Severe | 3 Severe flattening of condyle with loss of height, flat articular eminence/glenoid fossa ± large erosions/fragmentation of condyle |
MRI: magnetic resonance imaging; TMJ: temporomandibular joint.