PT27 - ULTRASOUND-BASED PREDICTION OF LUMBAR SKELETAL MUSCLE MASS IN CRITICALLY ILL PATIENTS: A COMPARISON WITH CT MEASUREMENTS

PT27

ULTRASOUND-BASED PREDICTION OF LUMBAR SKELETAL MUSCLE MASS IN CRITICALLY ILL PATIENTS: A COMPARISON WITH CT MEASUREMENTS

Q. H. Nguyen¹, T. N. Luu², C. H. L. Nguyen^3,*

¹ICU A9, Bach-mai hospital, Hanoi, ²Clincal Nutrition Department, Cho-ray hospital, Hochiminh, ³Center for Clinical Nutrition, Bach-mai hospital, Hanoi, Viet Nam

Rationale: Skeletal muscle area (SMA) at the third lumbar vertebra (L3), measured via computed tomography (CT), is an established proxy for total body muscle mass, though its use is often confined to clinical imaging. In contrast, bedside ultrasound offers a safer, more practical. This study aimed to identify the best ultrasound-based model for predicting CT L3 SMA

Methods: In this prospective cross-sectional study, 100 adult ICU patients who underwent CT scanning at the L3 level within 24 hours before or up to 48 hours after admission were included. Ultrasound measurements of muscle thickness were taken at two thigh landmarks (ventral and lateral) and two upper arm landmarks (anterior and anterolateral) with minimal probe compression. 

Results: Ultrasound muscle thickness at all four sites significantly correlated with CT muscle area (p < 0.001). The best-performing predictive model for CT L3 SMA included ultrasound thickness at the ventral thigh site, along with weight, age, and sex (R² = 0.73, p < 0.001). The mean difference between ultrasound-predicted and CT-measured SMA was 2.1 cm² (95% limits of agreement: −31.8 to +35.9 cm²)

Conclusion: Bedside ultrasound is a promising tool for assessing muscle mass at ICU admission. A single measurement at the ventral thigh, when combined with age, sex, and weight, reliably estimates CT-derived L3 SMA

References: 1. Meyer HJ, Wienke A, Surov A. Computed tomography–defined low skeletal muscle mass as a prognostic marker for short-term mortality in critically ill patients: A systematic review and meta-analysis. Nutrition. 2021;91-92:111417. doi:10.1016/j.nut.2021.111417

2. Fischer A, Hertwig A, Hahn R, et al. Validation of bedside ultrasound to predict lumbar muscle area in the computed tomography in 200 non-critically ill patients: The USVALID prospective study. Clin Nutr. 2022;41. doi:10.1016/j.clnu.2022.01.034

Disclosure of Interest: None declared