Muscle Ultrasound: A Narrative Review of Methodology and Relationships Between Muscle Ultrasound Thickness and Other Measures of Muscle Mass
Lian H. Cerella, Jane Ziegler, Garth S. NanniABSTRACT
Background
The lack of muscle ultrasound training and resources tailored to registered dietitian nutritionists (RDNs) has been a barrier to its clinical use. To better understand the clinical applicability of muscle ultrasound measurements, the primary aim of this narrative review was to identify and evaluate primary research studies assessing the relationship between ultrasound‐derived muscle thickness measures and other accepted measures of muscle mass. A secondary aim was to address the educational gap by providing a comprehensive summary of muscle ultrasound methodologies that can be used by RDNs in practice.
Methods
A review of the literature was completed in March 2026 using PubMed, SCOPUS, CINAHL and EMBASE. Studies were included from any year and if they were available in English. Articles were excluded if participants were less than 18 years old or included non‐human subjects. We reviewed studies using a systematic approach, looking for studies that examined the relationship between an ultrasound‐derived muscle thickness measure and another measure of muscle mass. We applied recommendations from the Academy of Nutrition and Dietetics' Evidence Analysis Process to evaluate methodological quality. Findings were synthesized using a narrative approach, with comparisons based on common findings across muscle sites. When p values for Pearson's or Spearman's rank correlation tests were missing, we contacted the corresponding authors for additional information.
Results
This narrative review included 25 primary research studies. Limited studies were available that evaluated the relationship between ultrasound‐derived temporalis, masseter, biceps, triceps, psoas and gastrocnemius muscle thickness measures and another measure of muscle mass. This review found that ultrasound‐derived quadriceps muscle thickness measures typically had a moderate, direct correlation with other body composition assessment measures. Muscle ultrasound methodologies were identified and detailed for eight muscle groups: temporalis, masseter, biceps, triceps, abdominal, psoas, quadriceps and gastrocnemius muscles.
Conclusions
We found that quadriceps muscle thickness typically had a moderate significant association with other measures of muscle mass. More research is needed to determine how ultrasound‐derived muscle mass measures can be applied in clinical practice. This review helps to address the gap in education for dietitians regarding reproducible muscle ultrasound methodology.