Reliability and validity of panoramic ultrasound for muscle quantification

This study examined the reliability and validity of using customized templates to acquire panoramic ultrasound (US) images for determining cross-sectional area (CSA) and volume in the vastus lateralis (VL), rectus femoris (RF), medial gastrocnemius (MG) and lateral gastrocnemius (LG). Panoramic US and magnetic resonance imaging (MRI) images were analyzed by two trained investigators. The inter-experimenter reliability (coefficient of variation [CV]) of panoramic US ranged from 2.4% to 4.1% and the intraclass correlation (ICC) ranged from 0.963 to 0.991, whereas the inter-experimenter CV of MRI ranged from 2.8% to 3.8% and the ICC from 0.946 to 0.986. Bland-Altman plots demonstrated high agreement between US and MRI; however, values obtained from MRI were systematically larger than those obtained from US. The present results indicate that using a customized US template provides reliable measures of leg muscle CSA and, thus, could be used to characterize muscle CSA and volume.