Intra- and Inter-Rater Reliability of Processing Ultrasound Tissue Characterization Scans in Midportion Achilles Tendinopathy

Table 4

Intra-rater and inter-rater reliability for the processing of UTC scans in quantifying the AoMD (n = 50).

Echo-type	Intra-rater reliability			Inter-rater reliability
	ICC (95% CI)	SEM	MDC	ICC (95% CI)	SEM	MDC
Echo-type I%	0.98 (0.97–0.99)	1.7	4.8	0.97 (0.92–0.98)	2.1	5.9
Echo-type II%	0.85 (0.75–0.91)	2.9	8.2	0.92 (0.86–0.95)	2.1	5.9
Echo-type III%	0.96 (0.94–0.98)	2.4	6.8	0.96 (0.92–0.98)	2.4	6.8
Echo-type IV%	0.94 (0.90–0.97)	1.7	4.6	0.97 (0.95–0.99)	1.2	3.3
Echo-type I + II%	0.96 (0.93–0.98)	3.5	9.8	0.98 (0.95–0.99)	2.5	6.9
Echo-type III + IV%	0.96 (0.93–0.98)	3.6	10.0	0.97 (0.94–0.98)	3.1	8.6

Intra-rater and inter-rater reliability are calculated for echo-types I, II, III, and IV individually, and combined for aligned fibrillar structure (echo-types I + II) and disorganized tendon structure (echo-types III + IV). CI: confidence interval: ICC: intraclass correlation coefficient: MDC: minimal detectable change (%); SEM: standard error of measurement (%); AoMD, area of maximum degeneration (1 slide in the Achilles tendon midportion with the lowest representation of echo-type I).