Monitoring skeletal muscle chronic fatty degenerations with fast T1-mapping

Objectives To develop a fast, high-resolution T1-mapping sequence dedicated to skeletal muscle imaging, and to evaluate the potential of T1 as a robust and sensitive biomarker for the monitoring of chronic fatty degenerations in a dystrophic disease. Methods The magnetic resonance imaging sequence consisted of the acquisition of a 1,000-radial-spokes FLASH echo-train following magnetisation inversion, resulting in 10s scan time per slice. Temporal image series were reconstructed using compressed sensing and T1 maps were computed using Bloch simulations. Ten healthy volunteers and 30 patients suffering from Becker muscular dystrophy (BMD) participated in this prospective study, in order to evaluate the repeatability, the precision and the sensitivity of the proposed approach. Intramuscular fat fraction (FF) was also measured using a standard three-point Dixon method. The protocol was approved by a local ethics committee. Results The mean T1 evaluated in the thighs muscles of healthy volunteers was 1,199 +/- 45 ms, with a coefficient of reproducibility of 2.3%. Mean T1 values were statistically decreased in the thighs of BMD patients and were linearly correlated with intramuscular FF (R = -0.98). Conclusions T1-mapping is a good candidate for fast, sensitive and quantitative monitoring of fatty infiltrations in neuromuscular disorders.