Reliability of Muscle Quantity and Quality Measured With Extended-Field-of-View Ultrasound at Nine Body Sites

Measuring muscle quantity and quality is very important because the loss of muscle quantity and quality is associated with several adverse effects specifically in older people. Ultrasound is a method widely used to measure muscle quantity and quality. One problem with ultrasound is its limited field of view, which makes it impossible to measure the muscle quantity and quality of certain muscles. In this study, we aimed to evaluate the intra- and inter-rater reliability of extended-field-of-view (EFOV) ultrasound for the measurement of muscle quantity and quality in nine muscles of the limbs and trunk. Two examiners took two ultrasound EFOV images with a linear probe from each of the muscle sites. The intraclass correlation coefficient (ICC) was used, and the standard error of measurement and coefficient of variation were calculated. Intra-rater reliability was good to excellent (ICC = 0.2–1.00) for all muscle measurements. The inter-rater reliability for most of the muscle measurements was good to excellent (ICC = 0.82–0.98). Inter-rater reliability was moderate (0.58–0.72) for some muscle quantity measurements of the tibialis anterior, gastrocnemius, rectus femoris, biceps femoris and triceps brachii muscles. Muscle quantity and quality can be measured reliably using EFOV US.