Reliability of musculoskeletal ultrasound imaging to measure supraspinatus tendon thickness in healthy subjects

[Purpose] The purpose of this study was to assess intra-rater and inter-rater reliability of musculoskeletal ultrasound (MSKUS) as a tool to measure supraspinatus tendon thickness in healthy subjects. [Subjects and Methods] Twenty healthy subjects were assessed in similar sitting position. Two experienced musculoskeletal ultrasound specialists measured supraspinatus tendon thickness. Tendon was measured twice in one day by each of two raters with an interval of one hour for within day reliability and was re-measured following one week for between days reliability. Data analysis was performed using the intraclass correlation coefficient (ICC) and standard error of measurement (SEM). [Results] Results reflected excellent within day intra-rater and inter-rater reliability with Mean ± standard deviation (SD)=5.14 ± 0.83 and 5.17 ± 0.78, ICC (2,1)=0.89–0.93 and ICC (2,2)=0.98 (0.95−0.99) and SEM=0.18–0.18 and 0.17 while between days intra-rater rater and inter-rater reliability with Mean ± SD=5.14 ± 0.83 and 5.17 ± 0.78, ICC(2,1)=0.88–0.90 and ICC(2,2)=0.95 (0.88−0.98), SEM=0.17–0.38 and 0.17 [Conclusion] The results of the current study indicate that MSKUS is a reliable tool for measuring supraspinatus tendon thickness in healthy subjects.