ICC for all calibration exercises. Values are ICC (IQR).
| Variables | All Readers, n = 6 | Pediatric Radiologists, n = 3 | SPARCC Developers, n = 2 | Rheumatologists, n = 2 |
|---|---|---|---|---|
| Exercise 1 | ||||
| Erosion | 0.37 (0.22–0.55) | 0.39 (0.15–0.61) | 0.72 (0.48–0.86) | 0.16 (−0.17 to 0.47) |
| Backfill | 0.39 (0.25–0.58) | 0.36 (0.14–0.58) | 0.82 (0.56–0.92) | 0.45 (0.12–0.69) |
| Fat metaplasia | 0.40 (0.25–0.58) | 0.46 (0.25–0.67) | 0.89 (0.77–0.95) | 0.82 (0.65–0.91) |
| Sclerosis | 0.42 (0.25–0.60) | 0.42 (0.17–0.65) | 0.61 (0.08–0.83) | 0.72 (0.49–0.86) |
| Ankylosis | 0.31 (0.17–0.49) | 0.46 (0.24–0.66) | 0.72 (0.49–0.85) | 0.19 (−0.16 to 0.51) |
| Exercise 2 | ||||
| Erosion | 0.54 (0.34–0.72) | 0.51 (0.16–0.74) | 0.96 (0.89–0.98) | 0.61 (0.32–0.79) |
| Backfill | 0.47 (0.31–0.64) | 0.12 (−0.08 to 0.38) | 0.90 (0.80–0.95) | 0.98 (0.95–0.99) |
| Fat metaplasia | – | – | – | – |
| Sclerosis | 0.47 (0.30–0.65) | 0.35 (0.13–0.58) | 0.88 (0.75–0.94) | 0.81 (0.63–0.90) |
| Ankylosis | – | – | – | – |
| Exercise 3 | ||||
| Erosion | 0.67 (0.54–0.80) | 0.67 (0.49–0.81) | 0.76 (0.21–0.91) | 0.66 (0.40–0.82) |
| Backfill | 0.33 (0.19–0.52) | 0.28 (0.07–0.51) | 0.43 (0.09–0.68) | 0.58 (0.27–0.77) |
| Fat metaplasia | 0.74 (0.62–0.85) | 0.76 (0.59–0.87) | 0.74 (0.53–0.87) | 0.75 (0.53–0.88) |
| Sclerosis | 0.63 (0.48–0.77) | 0.57 (0.36–0.75) | 0.69 (0.34–0.85) | 0.59 (0.30–0.78) |
| Ankylosis | 0.44 (0.28–0.62) | 0.20 (−0.02–0.45) | 0.84 (0.70–0.92) | 0.86 (0.73–0.93) |
Score ranges for each component of the SSS: erosion (0–40), backfill (0–20), fat metaplasia (0–40), sclerosis (0–40), ankylosis (0–20). Exercise 2 ICC scores not calculable for fat metaplasia and ankylosis owing to an insufficient number of abnormalities present within the cohort of selected subjects for that exercise. ICC: intraclass correlation coefficients; IQR: interquartile range; SPARCC: Spondyloarthritis Research Consortium of Canada; SSS: Sacroiliac joint Structural Score.