Diagnostic accuracy and potential clinical role of muscle ultrasound in sarcopenia: An updated systematic review

Abstract

Objective: To evaluate the diagnostic accuracy of muscle ultrasound parameters for sarcopenia and determine whether this method can complement conventional assessment. Methods: A systematic review of diagnostic accuracy studies was conducted in accordance with PRISMA-DTA. PubMed/MEDLINE was searched, with supplementary searches in Europe PMC, Crossref, ClinicalTrials.gov, and study reference lists through September 17, 2026. Studies comparing quantitative ultrasound parameters with explicit diagnostic criteria for sarcopenia were included. Risk of bias was assessed using QUADAS-3. Results: Forty-five publications were included in the diagnostic accuracy synthesis. The rectus femoris was the most frequently investigated muscle, mainly through muscle thickness and cross-sectional area. Twelve studies provided verifiable 2 × 2 tables. In the three comparable studies of rectus femoris cross-sectional area, sensitivity ranged from 62.5% to 100% and specificity from 53.8% to 92.0%. Clinical and methodological heterogeneity precluded a valid meta-analysis. Of the 41 studies assessed with QUADAS-3, 38 had an overall high risk of bias. Conclusion: Muscle ultrasound may support screening and complement sarcopenia assessment, particularly because it is portable and suitable for bedside use. However, variation in protocols, muscles, diagnostic criteria, and cutoffs currently prevents its use as a replacement for conventional methods.