Muscle ultrasound for nutrition assessment: Practical clinical protocols

Muscle ultrasound (mUS) is an emerging and increasingly utilized tool for assessing body composition. Bedside mUS can provide reliable measurements of skeletal muscle and adipose tissue that can strengthen nutrition assessment. As current malnutrition diagnostic frameworks emphasize the evaluation of lean body mass, mUS offers a practical, radiation-free, serial, and accessible method for quantifying muscle status in real time. This review summarizes the existing literature on mUS-based body composition assessment, introduces the technical skills needed for high-quality image acquisition, describes the measurements that may be useful in the assessment of malnutrition, and outlines the need for skills-based training programs. Key parameters include muscle layer thickness, cross-sectional area, echo intensity, pennation angle, and fascicle length. Normative reference values and longitudinal changes are reviewed, as each can help clinicians identify low muscle mass and track meaningful changes over time. Despite the advantages of mUS, adoption within routine nutrition practice remains inconsistent. Limited standardization of acquisition protocols and insufficient access to structured, hands-on operator training continue to hinder reproducibility across clinical settings. Further implementation studies are needed to ensure high-quality measurements are conducted and incorporated into nutritional assessment.