Sex (% female) | 85% |
Median (range) age (years) | 55 (17–78) |
Median (range) symptom duration (years) | 1.5 (0.5–15) |
Median (range) tender joint count (0–40) | 6 (0–30) |
Median (range) swollen joint count (0–40) | 4 (2–18) |
Median (range) serum CRP (mg/l) | 10 (<8–102) |
Median (range) ESR (mm/h) | 8 (1–54) |
Median (range) IgM rheumatoid factor (IU/ml) | 10 (<8–102) |
Conventional radiography (no of patients) | |
Normal | 19 |
Compatible with RA (Larsen grade 1) | 5 |
Minimal OA changes | 13 |
Calcinosis | 4 |
MRI synovitis (no of patients) | |
Normal | 15 |
Compatible with RA | 23 |
Compatible with OA | 2 |
Compatible with RA/OA | 0 |
Only tenosynovitis | 1 |
MRI erosions (no of patients) | |
Normal | 27 |
Compatible with RA | 14 |
Compatible with OA | 0 |
Compatible with RA/OA | 0 |
Bone scintigraphy* (no of patients) | |
Normal | 14 |
Compatible with RA | 10 |
Compatible with OA | 10 |
Compatible with RA/OA | 4 |
RA, rheumatoid arthritis; OA, osteoarthritis.
Larsen grade 1 denotes the presence of joint space narrowing, soft tissue swelling and/or juxta-articular osteoporosis.
MRI synovitis patterns: compatible with RA: several joints, not 1st carpometacarpal (CMC1) joints; compatible with OA: CMC1; compatible with RA/OA: mixed involvement of CMC1 and other joints.
MRI erosion patterns: compatible with RA: other joints than CMC1; compatible with OA: CMC1; compatible with RA/OA: mixed involvement of CMC1 and other joints.
Scintigraphic patterns: compatible with RA: several joints but not distal interphalangeal (DIP) joints and CMC1; compatible with OA: CMC1 or proximal interphalangeal (PIP) and DIP joints; compatible with RA/OA: mixed involvement of CMC1/DIP joints and other joints, eg, MCP/wrist joints.
*In three patients bone scintigraphy was not performed.