Table 1. Comparison of Reader 1 and Reader 2 for pre-treatment MRI assessment (ASspiMRI-a score) and showing the number of affected VUs per patient and the number of erosions per vertebral unit. The ICC between readings is shown, as well as the overall correlation (Spearman Rank correlation) and p-value.
| Reader 1 |
Reader 2 |
||||
| Assessment | STIR | T1W/Gd | STIR | T1W/Gd | |
| Pre-treatment | |||||
| ASspiMRI-a | 9.53 (±5.75) | 11.00 (±5.52) | 6.72 (±5.11) | 7.91 (±6.19) | |
| No. of affected VU | 6.9 (±4.3) | 8.3 (±3.4) | 5.0 (±3.5) | 5.7 (±3.6) | |
| No. of affected VUs with erosions | 0.6 (±0.9) | 0.8 (±1.0) | 0.5 (±0.8) | 0.65 (±1.2) | |
| ICC | 0.69 (±0.23) | 0.65 (±0.21) | |||
| Spearman's r | 0.85 (p<0.0001) | 0.88 (p<0.0001) | |||
| p-value | 0.019 | 0.03 | |||
| Post-treatment | |||||
| ASspiMRI-a | 4.56 (±4.28) | 7.97 (±4.82) | 3.59 (± 3.71) | 5.31 (±5.17) | |
| Spearman's r | 0.85 (p<0.0001) | 0.88 (p<0.0001) | |||
| p-value | 0.001 | <0.0001 | |||
| ASspiMRI-a score reduction | 4.97 (±4.36) | 3.03 (±3.49) | 3.12 (± 3.58) | 2.59 (±2.85) | |
| ASspiMRI-a score reduction in % | 50.8 (±33.6) | 25.3 (±35.3) | 42.4 (±50.4) | 32.9 (±35.6) | |
| p-value for score reduction | <0.0001 | <0.0001 | <0.0001 | <0.0001 | |
ASspiMRI-a, ankylosing spondylitis spine MRI-activity; ICC, intraclass correlation coefficient; No., number; STIR, short tau inversion–recovery; T1W, T1 weighted gadolinium contrast-enhanced technique; VU, vertebral units.