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

Objective: 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 mea-sure muscle quantity and quality. One problem with ultrasound is its limited field of view, which makes it impos-sible 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.Methods: 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 varia-tion were calculated.Results: 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 reli-ability was moderate (0.58-0.72) for some muscle quantity measurements of the tibialis anterior, gastrocnemius, rectus femoris, biceps femoris and triceps brachii muscles.Conclusion: Muscle quantity and quality can be measured reliably using EFOV US.