J Magn Reson Imaging. 2026 Jun 11. doi: 10.1002/jmri.70377. Online ahead of print.
ABSTRACT
BACKGROUND: Muscle mass decline, associated with strength decline, is a hallmark of aging. Yet, strength decline greatly exceeds mass decline. This indicates that aspects of muscle quality and architecture-not reflected by mass-also influence force generating capacity. Additionally, shape modeling enables analysis of the shape variations of muscles beyond size.
PURPOSE: To predict muscle strength using muscle features beyond muscle quantity.
STUDY TYPE: Retrospective cross-sectional study.
POPULATION: Twenty-four healthy subjects normally distributed over an age range between 30 and 79 years old with a balanced sex distribution (12 female).
FIELD STRENGTH/SEQUENCE: 3 T MRI using multi-echo Dixon and Stejskal-Tanner DTI.
ASSESSMENT: Shape-only and shape + architecture models were generated using water-only and DTI images of the quadriceps. Multiple linear mixed-effects models were produced using (1) volume, (2) shape-only, and (3) shape + architecture. Volume was not added to the shape-only and shape + architecture models. Features reaching statistical significance within the models were retained for further analysis. Models’ performance was evaluated using leave-one-subject-out (LOSO) cross-validation (CV).
STATISTICAL TESTS: Pairwise, subject-level bootstrapping comparison was conducted and ∆R2 and ∆RMSE with 95% confidence interval (CI) were calculated. The improvement was considered statistically significant when both ∆R2 and ∆RMSE are positive and the 95% CI did not contain zero. Positive ∆R2 and ∆RMSE indicate an increase in R2 and a decrease in RMSE values.
RESULTS: Shape-only features demonstrated an improvement in the model performance compared to muscle volume. Models were significantly improved for the vastus lateralis to predict eccentric torque-∆R2 = 0.16 (0.01-0.29), ∆RMSE = 5.0 (0.4-9.7); and for the vastus intermedius predicting isometric torque-∆R2 = 0.19 (0.02-0.36), ∆RMSE = 6.5 (0.7-12.0). Shape + architecture features did not significantly improve the performance (all p ≥ 0.131).
DATA CONCLUSION: Shape-only models are promising to quantify variations of muscle shape related to force production, and have the potential to develop imaging-based biomarkers for muscle strength in diseases.
EVIDENCE LEVEL: 3.
TECHNICAL EFFICACY: Stage 2.
PMID:42277391 | DOI:10.1002/jmri.70377
