Table 3.

Interobserver ICC values [overall and mean (range) of all possible reader pairs] and SDC for 2-year (exercises 1 and 2) and 1-year (exercise 3) change in SPARCC MRI SIJ SSS in patients with SpA.

Exercise Patient No.ReadersFat MetaplasiaErosionBackfillAnkylosis
Overall ICCMean ICC (range)SDCOverall ICCMean ICC (range)SDCOverall ICCMean ICC (range)SDCOverall ICCMean ICC (range)SDC
Exercise 1, n = 4540.440.44 (0.29–0.64)0.9 (2.3)0.390.38 (0.27–0.45)1.4 (3.5)0.560.54 (0.46–0.66)1.3 (6.6)0.640.65 (0.58–0.74)0.5 (2.3)
Exercise 2, n = 10220.581.3 (3.3)0.402.1 (5.3)0.491.8 (9.0)0.730.9 (4.4)
Exercise 3, n = 4030.610.61 (0.51–0.79)0.9 (2.2)0.540.54 (0.48–0.60)1.7 (4.4)0.420.43 (0.19–0.63)1.2 (5.8)0.470.48 (0.29–0.69)1.2 (6.0)
  • ICC: intraclass correlation coefficient; SPARCC: the Spondyloarthritis Research Consortium of Canada; MRI: magnetic resonance imaging; SIJ: sacroiliac joint; SSS: Sacroiliac joint Structural Score; SpA: spondyloarthritis; SDC: smallest detectable change.