Lipid content in the musculature of the lower leg assessed by fat selective MRI: intra- and interindividual differences and correlation with anthropometric and metabolic data.

Purpose: To assess the muscular lipid content (LC) in different muscle groups of the lower leg by a magnetic resonance imaging technique working with chemical shift selective excitation, and comparison with anthropometric and metabolic data.
Materials and Methods: Examinations were performed in 67 volunteers (54 male/13 female, age 29 +/- seven years) on a 1.5 T whole body imager, applying a highly selective spectral-spatial technique for fat selective MRI. LC was measured in six calf muscles and correlated with body mass index (BMI), percent body fat (PFAT), and insulin sensitivity (IS) of the subjects.
Results: Mean muscular LC of all subjects was between 2.0% (Tibialis posterior [TP]) and 3.8% (Peroneus muscles) with female subjects showing a significantly higher LC in all muscle groups (P < 0.05 each). LCs correlated moderately with BMI (R between 0.39 [TP] and 0.53 [GM]) and with PFAT (R between 0.38 [TP] and 0.62 [GM]). Insulin-resistant subjects showed slightly but not significantly increased LC compared to insulin-sensitive subjects in BMI-matched subgroups.
Conclusion: The fat-selective MRI technique allows a reliable non-invasive measure of muscular lipids - even in muscle groups with inherent low LC - within a relatively short measurement time of about three minutes. The presented data reveal interesting interrelationships between LC and anthropometric and metabolic data, and therefore provide new insight into muscular fat metabolism.
(Copyright 2003 Wiley-Liss, Inc.)