Table 3

Intraclass correlation coefficients and smallest detectable change for scorings of radiographs and CT and volume measurements on CT

	ICC status score			ICC change score		SDC (SDC%)
	0 months	6 months	12 months	0–6 months	0–12 months	6 months	12 months
S/vdH total score	0.98	0.99	0.99	0.15	0.49	2.9 (2.6)	1.8 (1.6)
S/vdH erosion score	0.95	0.94	0.94	0.35	0.17	1.3 (2.4)	1.1 (2.0)
S/vdH narrowing score	0.97	0.98	0.97	0.50	0.76	1.9 (2.4)	1.4 (1.7)
CT erosion score	0.97	0.96	0.96	0.95	0.89	0.3 (0.5)	0.7 (1.2)
CT erosion volume	0.99	0.99	0.99	0.89	0.93	19 (1.6)	17 (1.5)

CT, computed tomography; ICC, intraclass correlation coefficient; SDC, smallest detectable change; SDC%, SDC as a percentage of actually obtained maximum score; S/vdH, Sharp/van der Heijde.