Definitions and scaling of features included in the OMERACT hand OA MRI score.
| Definition | Scaling | |
|---|---|---|
| Synovitis# | Thickened synovium with enhancement of gadolinium | 0 = Normal, 1 = Mild, 2 = Moderate, 3 = Severe |
| Erosive damage# | Subchondral bone loss, including erosions, bone attrition, and bone resorption | 0 = Normal; 1 = Mild, ≤ 10% of bone volume or ≤ 25% joint surface affected*; 2 = Moderate, 11–20% of bone volume and/or 26–50% of joint surface affected*; 3 = Severe, > 20% of bone volume and/or > 50% of joint surface affected* |
| Cyst | A sharply marginated bone lesion with typical signal characteristics* without a cortical break. *Increased signal intensity on T1w FS, T2w FS or STIR images | 0 = Normal; 1 = Mild, ≤ 10% of bone volume*; 2 = Moderate, 11–20% of bone volume*; 3 = Severe, > 20% of bone volume* |
| Osteophyte | Abnormal bone protuberance at joint margins or surfaces | 0 = Normal, no osteophytes; 1 = Mild, 1–3 small osteophytes; 2 = Moderate, ≥ 4 small osteophytes and/or ≥ 1 moderate osteophyte(s); 3 = Severe, at least 1 large osteophyte |
| Cartilage space loss | Loss of the cartilage space based on the interbone distance | 0 = Normal; 1 = Mild, loss of cartilage space without bone-to-bone contact; 2 = Moderate, focal complete loss of cartilage space; 3 = Severe, complete cartilage space loss affecting > 50% of the articulating joint area |
| Malalignment | Angulation or subluxation of joints in the frontal plane | 0 = No apparent malalignment; 1 = Mild, ≤ 10° angulation and/or not congruent joint surfaces; 2 = Moderate, 11–20° angulation and/or moderate subluxation without crossing the midline; 3 = Severe, > 20° angulation and/or subluxation with crossing the midline |
| Bone marrow lesions# | A lesion within the trabecular bone with signal characteristics consistent with increased water content (i.e., high signal intensity on STIR images or T2w FS images) and with ill-defined margins. | 0 = Normal; 1 = Mild, 1–33% of bone volume*; 2 = Moderate, 34–66% of bone volume*; 3 = Severe, 67–100% of bone volume* |
↵* “Bone volume” and “joint surface” refer to the proximal and distal part of the joint combined. The assessed bone volume should extend from the articular surface to a depth of 0.5 cm for DIP joints and 1.0 cm for PIP joints.
↵# 0.5 increments for the assessment of synovitis, erosions, and bone marrow lesions. T1w: T1-weighted; T2w: T2-weighted; FS: fat-suppressed; STIR: short-tau inversion recovery; OA: osteoarthritis; MRI: magnetic resonance imaging; DIP: distal interphalangeal; PIP: proximal interphalangeal.