Reliability and Validity of Panoramic Ultrasound Imaging for Evaluating Muscular Quality and Morphology: A Systematic Review

Panoramic ultrasound (US) is a novel method used to assess linear dimensions, cross-sectional area, fatty infiltrate and echo-intensity features of muscles that cannot be measured with B-mode US. However, a structured overview of its validity and reliability is lacking. MEDLINE, PubMed, SCOPUS and Web of Science databases were systematically searched for studies evaluating reliability or validity data on panoramic US imaging to determine the muscular morphology and/or quality of skeletal muscles. Most studies had acceptable methodological quality. Seventeen studies analyzing reliability (n = 16) or validity (n = 5) were included. Twelve studies assessed cross-sectional area, seven studies assessed echo-intensity, five assessed linear dimensions (fascicle/tendon length, muscle/subcutaneous adipose thickness or between-structure distance) and one assessed intramuscular fat. Panoramic US seems to be a reliable and valid tool for the assessment of muscle morphology and quality in healthy populations at specific locations, particularly the lower extremities. Studies including scanning procedures are needed to confirm these findings in locations not included in this revision and in both clinical and healthy populations.