Agreement between ultrasound, MRI, conventional radiography and clinical examination for structural and soft tissue changes
| PEA | κ (95% CI) | |||||
|---|---|---|---|---|---|---|
| US1 vs US2 (%) | MRI1 vs MRI2 (%) | US1 vs MRI1 (%) | US1 vs US2 | MRI1 vs MRI2 | US1 vs MRI1 | |
| Bone erosions | ||||||
| All | 96 | 90 | 78 | 0.90 (0.83 to 0.97) | 0.76 (0.64 to 0.88) | 0.55 (0.40 to 0.70) |
| PIP joint (total) | 96 | 88 | 79 | 0.88 (0.76 to 1.0) | 0.68 (0.62 to 0.74) | 0.43 (0.17 to 0.70) |
| EOA | 93 | 87 | 78 | 0.84 (0.69 to 0.99) | 0.65 (0.55 to 0.75) | 0.50 (0.20 to 0.80) |
| Non-EOA | 100 | 91 | 80 | 1.0 | 0.70 (0.62 to 0.78) | –* |
| DIP joint (total) | 96 | 91 | 77 | 0.90 (0.81 to 1.0) | 0.78 (0.72 to 0.85) | 0.53 (0.32 to 0.74) |
| EOA | 92 | 91 | 75 | 0.83 (0.68 to 0.99) | 0.70 (0.55 to 0.86) | 0.36 (0.08 to 0.64) |
| Non-EOA | 100 | 93 | 80 | 1.0 | 0.80 (0.70 to 0.90) | 0.52 (0.12 to 0.93) |
| Osteophytes/bony nodules | ||||||
| All | 92 | 61 | 76 | 0.83 (0.75 to 0.91) | 0.15 (0.04 to 0.27) | 0.51 (0.35 to 0.66) |
| PIP joint (total) | 94 | 46 | 73 | 0.87 (0.77 to 0.96) | 0.14 (0.03 to 0.24) | 0.48 (0.27 to 0.69) |
| EOA | 90 | 44 | 67 | 0.77 (0.59 to 0.94) | 0.15 (0.02 to 0.28) | 0.35 (0.10 to 0.60) |
| Non-EOA | 98 | 50 | 85 | 0.96 (0.88 to 1.0) | –* | 0.70 (0.39 to 1.01) |
| DIP joint (total) | 91 | 75 | 79 | 0.78 (0.63 to 0.92) | 0.07 (0.03 to 0.11) | 0.43 (0.16 to 0.70) |
| EOA | 90 | 86 | 81 | 0.70 (0.45 to 0.94) | −0.05 (−0.12 to 0.03) | 0.26 (−0.13 to 0.65) |
| Non-EOA | 93 | 55 | 75 | 0.84 (0.66 to 1.0) | 0.10 (0.00 to 0.20) | 0.50 (0.14 to 0.86) |
| Synovitis | ||||||
| All | 98 | 85 | 87 | 0.93 (0.86 to 1.0) | 0.58 (0.40 to 0.76) | 0.55 (0.35 to 0.76) |
| PIP joint (total) | 96 | 83 | 92 | 0.90 (0.80 to 1.0) | 0.42 (0.11 to 0.73) | 0.75 (0.52 to 0.98) |
| EOA | 95 | 81 | 89 | 0.89 (0.76 to 1.0) | 0.41 (0.05 to 0.77) | 0.68 (0.39 to 0.97) |
| Non-EOA | 98 | 88 | 100 | 0.90 (0.70 to 1.1) | 0.43 (0.23 to 0.63) | 1.0 |
| DIP joint (total) | 100 | 87 | 81 | 1.0 | 0.68 (0.47 to 0.89) | 0.36 (0.06 to 0.65) |
| EOA | 100 | 89 | 75 | 1.0 | 0.77 (0.55 to 0.98) | 0.36 (0.08 to 0.64) |
| Non-EOA | 100 | 81 | 94 | 1.0 | –* | –* |
| Effusion | ||||||
| All | 92 | 75 | 73 | 0.84 (0.76 to 0.92) | 0.50 (0.35 to 0.65) | 0.41 (0.23 to 0.59) |
| PIP joint (total) | 91 | 73 | 75 | 0.80 (0.67 to 0.92) | 0.41 (0.18 to 0.65) | 0.33 (0.31 to 0.36) |
| EOA | 87 | 69 | 72 | 0.68 (0.48 to 0.88) | 0.43 (0.20 to 0.66) | 0.26 (0.08 to 0.61) |
| Non-EOA | 96 | 80 | 80 | 0.91 (0.80 to 1.0) | 0.23 (0.08 to 0.38) | 0.47 (0.04 to 0.90) |
| DIP joint (total) | 94 | 77 | 71 | 0.89 (0.79 to 0.98) | 0.54 (0.33 to 0.75) | 0.42 (0.19 to 0.66) |
| EOA | 90 | 75 | 69 | 0.79 (0.62 to 0.96) | 0.42 (0.13 to 0.71) | 0.40 (0.11 to 0.68) |
| Non-EOA | 100 | 80 | 75 | 1.0 | 0.38 (0.12 to 0.64) | 0.39 (0.03 to 0.75) |
Values are presented as percentages of exact agreement (PEA) and unweighted κvalues (κ(95% CI)). The imaging modalities were ultrasonography, MRI and conventional radiography. To study interobserver reliability, agreement was studied for ultrasound between ultrasonographer 1 (RW, US1) and ultrasonographer 2 (PC, US2), and for MRI between MRI radiologist 1 (LJ, MRI1) and MRI radiologist 2 (VL, MRI2).
↵* Not possible to calculate κvalue because of empty cell in 2×2 table.
DIP, distal interphalangeal; EOA, erosive osteoarthritis; PIP, proximal interphalangeal.