Validity of real time ultrasound for measuring skeletal muscle size

Objectives: To identify what is known about the validity of real time ultrasound (RTUS) measurements of skeletal muscle size and to summarise populations and conditions that have been assessed with RTUS. Methods: Seven databases were searched for potential study inclusion. All identified studies were assessed with inclusion criteria and a quality assessment scale. Each study reported muscle size measurements with RTUS and a reference standard (either MRI or CT). Muscle sizes were measured as a muscle thickness (linear dimension), a muscle area (cross sectional area or CSA) or as a muscle volume (anatomical cross sectional area or ACSA). Results: Thirteen studies were identified for inclusion in this systematic review. Measures of correlation coefficient, coefficient of determination and mean effect size changes were determined. All of the studies in the review came to the same conclusion - that RTUS is a valid alternative to objectively measure muscle size when compared to gold standards such as MRI or CT. Discussion: All the studies in the review came to the conclusion that RTUS can provide valid measurements of skeletal muscle. The populations represented in this review were adequately varied to warrant generalisation of the results.