Examination of the Intra-rater Reliability of Ultrasound Measures of Supraspinatus and Infraspinatus Echo Intensity

Abstract

[Purpose] We investigated the intra-rater reliability of ultrasound measures of supraspinatus and infraspinatus echo intensity. [Participants and Methods] The subjects were 30 healthy male adults and measurements were made using an ultrasound device. Intraclass correlation coefficients (ICC) and measurement error by 95% confidence intervals of minimum detectable change (MDC₉₅) were obtained for the same and different days. Bland-Altman analysis was used to determine the presence of systematic errors. [Results] For measurements on the same day, the ICC (1,1) was 0.96 for the supraspinatus and 0.97 for the infraspinatus. MDC₉₅ was 9.3 for the supraspinatus, and 7.2 of the infraspinatus. For measurements on different days, the ICC (1,2) was 0.97 for the supraspinatus and 0.98 for the infraspinatus. MDC₉₅ was 7.6 for the supraspinatus and 5.9 for the infraspinatus. There were no systematic errors in either the same day or the different day measurements. [Conclusion] Ultrasound measures of supraspinatus and infraspinatus echo intensity are reliable for both same day and different day measurements.