Protron spin‐lattice relaxation time of duchenne dystrophy skeletal muscle by magnetic resonance imaging

By means of proton MRI, the spin‐lattice relaxation times ( T 1 values) of pelvic and leg muscles were measured in Duchenne muscular dystrophy (DMD) patients and normal controls. The bound water fraction (BWF) was calculated from the T 1 value obtained. In normal children, the T 1 value decreased, and BWF increased with age. In DMD, the T 1 value rapidly decreased, from an abnormally high value in the early stages, with the progress of the disease. This reduction of the T 1 value in DMD was not the same for all muscles; it was most prominent in the gluteus maximus and least prominent in the sartorius and gracilis muscles. BWF was below normal in the early stages of DMD . It is suggested that both regenerating and degenerating muscle fibers, together with the increased muscle water content, cause the high T 1 value and low BWF in the early stages of DMD, whereas replacement of muscle by fat causes the decreased T 1 value in the advanced stages.