Reliability of Ultrasound Diagnostic Equipment in Measuring the Cross-sectional Area and Muscle Brightness of the Flexor Digitorum Superficialis

Abstract

[Purpose] The Cross-Sectional Area (CSA) and muscle brightness of the Flexor Digitorum Superficialis muscle (FDS) was measured using ultrasound diagnostic equipment, and the reliability of these measurements was examined. [Participants and Methods] The subjects were 10 adults with no history of elbow injury. Reliability was examined using the intraclass correlation coefficient (ICC), and the 95% confidence interval of the minimum detectable change (MDC₉₅) was calculated. [Results] For measurements on the same day and on the different days, the inter-rater reliability ICC was 0.77 or higher. There were no systematic errors in any of the measurements. The MDC₉₅ of same-day intra-rater measurements of CSA and muscle brightness were 15.8 mm² and 7.5 at the humeral trochlea height, and 8.3 mm² and 9.9 at the coronoid process height, respectively. Those of different day, intra-rater measurements were 16.1 mm² and 17.2 at the humeral trochlea, and 16.9 mm² and 17.5 at the coronoid process height. The inter-rater measurements were 14.4 mm² and 13.3 at the humeral trochlea, and 12.5 mm² and 10.8 at the coronoid process. [Conclusion] The results of this study indicate that ultrasound can be used to quantitatively and qualitatively evaluate the FDS.