A recent study suggests that a simple muscle ultrasound may potentially detect early muscle deterioration and insulin resistance (important early steps toward type 2 diabetes), well before they are detected in routine bloodwork. A recent study suggests an easy-to-perform muscle ultrasound may potentially detect early muscle deterioration and insulin resistance (important early steps toward type 2 diabetes), well before they are detected in routine bloodwork.
A growing body of literature indicates that obesity (now greater than 40% of adults in the US) can lead to fat buildup within muscle (muscle lipotoxicity), which induces inflammation, disrupts insulin signalling, and leads to insulin resistance (the precursor to T2D). Once T2D is initiated, people typically experience muscle deterioration and a higher likelihood of developing other(related) diseases.
Although general awareness that prediabetes and T2D can take irreversible forms has been increased, as many people are still completely unaware that they have these conditions, thus, by the time they have been diagnosed, irreversible changes may have occurred. Current testing procedures for insulin resistance can measure state precisely (e.g., hyperinsulinemic-euglycemic clamp), but they are invasive, expensive, and impractical for routine care.
Researchers at the University of Michigan (IRB HUM00242823) investigated whether a non-invasive skeletal muscle ultrasound could detect these changes earlier and more easily.
The study recruited 20 adults with obesity (BMI 30–40 kg/m²) and no prior diagnosis of diabetes, along with five healthy lean controls (BMI 18.5–24.9 kg/m²). All participants fasted for twelve hours before their scans, and a trained musculoskeletal radiologist used a high-frequency ultrasound probe to capture images of the deltoid and vastus lateralis muscles. Two blinded researchers measured skeletal muscle echo intensity (MEI) using proprietary software.
The results demonstrated significant differences. Individuals with obesity had greater MEI values than the lean controls, with the MEI of the vastus lateralis muscle being approximately 122% higher (P < 0.001). The mean MEI of the obese group’s vastus lateralis was 107 ± 29.6 as compared to 48.1 ± 16.5 for healthy controls. The deltoid muscle exhibited similar differences (85 ± 29.2 vs. 33.7 ± 8.6). There was excellent reliability between the two researchers, with the intraclass correlation coefficients for the deltoid muscle being: 95% CI: 0.96–0.997, and for the vastus lateralis: 95% CI: 0.986–0.999.
Of the obese group, sixteen participants underwent the gold-standard clamp test for insulin sensitivity. The average M value for the obese participants was 26.6 ± 10.5 µmol/kg of fat-free mass per minute, which was less than half the normal mean of 55.8 ± 9.2 (P < 0.001). Half of the participants met the criteria for being insulin resistant, and 43.8% showed impaired sensitivity. Importantly, all subjects with insulin resistance had increased MEI. This suggests that ultrasound has potential as a pre-monitor.
MEI also had a significant correlation with muscle mass. MEI displayed a negative correlation with appendicular skeletal muscle index (ASMI); r = -0.76, P < 0.001 for the vastus lateralis and r = -0.67, P = 0.001 for the deltoid. The fat-free mass index (FFMI) demonstrated a similar trend; r = -0.74, P < 0.001, vastus lateralis r = -0.69, P < 0.001, deltoid. Interestingly, MEI did not show a significant correlation with body mass index (BMI) but did show a moderate negative correlation with bodyweight (vastus: r = -0.61, P = 0.004; deltoid: r = -0.57, P = 0.009).
Although the authors acknowledge limitations such as small sample size and the absence of muscle biopsies, they remain optimistic that handheld ultrasound devices—often dubbed the “stethoscope of the future”—could enable widespread clinical adoption.
Researchers hope that as AI continues to develop, these scans could occur rapidly at the bedside, allowing individuals at risk to be flagged long before complications develop. This has the potential to help millions intervene with diabetes and muscle loss long before the damage becomes silent and irreversible. If validated by larger studies, muscle ultrasound could transform the early detection and management of one of society’s most pervasive and costly health threats.
References: Soliman SB, Chugh OK, Leuteneker JE, et al. Muscle ultrasound: a novel noninvasive tool for early detection of developing insulin resistance and lower muscle mass in obesity. J Ultrasound Med. Published online June 12, 2025. doi:10.1002/jum.16741
