Muscle measures from computed tomography, bioelectrical impedance, and ultrasound in hematopoietic cell transplantation patients

Background: Low muscle mass is associated with adverse outcomes following hematopoietic cell transplantation (HCT). Computed tomography (CT) is a gold standard approach to measuring skeletal muscle but is associated with radiation exposure and no longer routinely performed in all patients before HCT. Alternative methods are needed for early identification, intervention, and serial evaluation of low muscle mass after HCT. Optimal methods should be portable and readily accessible. We thus evaluated the correlation between quadriceps muscle ultrasound (US), whole-body bioelectrical impedance analysis (BIA), and muscle CT in patients planned to undergo HCT. Methods: This study included 71 consecutive patients ≥18 years who underwent first HCT between 2020 and 2024. Pearson correlation examined the relationship between skeletal muscle measurements of cross-sectional area (CSA) from CT images at the third lumbar vertebra (L3), whole-body skeletal muscle mass (SMM) from BIA, and CSA from quadriceps muscle US. Results: Median age at evaluation was 52.6 years (range: 18.6–76.6). CT-derived L3 skeletal muscle CSA positively correlated with quadriceps muscle US CSA (r = 0.73; P < 0.0001) and BIA SMM (r = 0.92; P < 0.0001). Quadriceps muscle US and BIA SMM were also positively correlated (r = 0.74; P < 0.0001). Positive correlations were consistent across body mass index (BMI) and age categories. Conclusions: Quadriceps muscle US and whole-body BIA offer reliable alternatives to estimate skeletal muscle without radiation exposure. US is more readily available, allowing for detailed phenotypic evaluation of individual muscles and identification of muscle compromise that may occur following HCT. This can enable development and monitoring of tailored and targeted interventions to improve muscle health and HCT outcomes.