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Table 2 Reliability of change scores for the SIS and SSS components

From: Spondyloarthritis Research Consortium of Canada sacroiliac joint inflammation and structural scores: change score reliability and recalibration utility in children

 Change scores ICC (95% CI)
ComponentAll raters
N = 6
Pediatric radiologists N = 3SPARCC developers
N = 2
Scoring exercise 1
 Inflammation0.8 (0.69–0.89)0.84 (0.7–0.92)0.96 (0.9–0.98)
 Backfill0.3 (0.1–0.62)0.49 (0.14–0.79)− 0.74 (− 0.92–0.09)
 Fat metaplasia0.46 (0.23–0.75)0.55 (0.19–0.82)0.29 (− 0.34–0.73)
 Sclerosis0.53 (0.3–0.79)0.49 (0.14–0.8)0.46 (− 0.12–0.81)
 Erosion0.38 (0.16–0.69)0.6 (0.26–0.85)0.33 (− 0.19–0.74)
 Ankylosis0.06 (− 0.07–0.35)0 (− 0.29–0.44)0 (0–0)
Scoring exercise 2
 Inflammation0.83 (0.71–0.92)0.85 (0.7–0.93)0.82 (0.6–0.93)
 Backfill0.54 (0.35–0.75)0.52 (0.24–0.76)0.88 (0.71–0.95)
 Fat metaplasia0.65 (0.47–0.82)0.92 (0.84–0.97)0.17 (− 0.3–0.58)
 Sclerosis0.33 (0.15–0.58)0.38 (0.1–0.67)0.41 (− 0.07–0.73)
 Erosion0.60 (0.41–0.79)0.65 (0.4–0.84)0.72 (0.4–0.89)
 Ankylosis0.96 (0.93–0.98)0.94 (0.87–0.97)1 (1–1)
  1. Legend: SIS measures inflammation and had N = 26 and N = 19 subjects for scoring exercises 1 and 2. SSS components include backfill, fat metaplasia, sclerosis, erosion, and ankylosis with N = 12 and N = 18 subjects for scoring exercises 1 and 2, respectively. The acceptability thresholds for change scores were ICC > 0.7 for SIS and > 0.5 for all SSS components
  2. SIS sacroiliac joint inflammation score, SSS sacroiliac joint structural score, ICC intraclass correlation coefficient