Change of MR Diffusion Property During Active Muscle Contraction in the Calf

Yoshikazu Okamoto¹, Akira Kunimatsu², Manabu Minami³

We obtained diffusion tensor images (b=500 s/mm) of bilateral calves of ten volunteers in a 1.5T MR machine at resting and planter flexion states of the right ankle. In gastrocnemius medialis (GCM), the FA, 1 and 2 of right to left ratios were increased from 1.05,0,99, and 0.99 to 1.17 (P<0.05), 1.06 (P<0.01), and 1.07 (P<0.01) with statistically significant difference by Paired t-test. In anterior tibialis (AT), 1 and 2 ratios were decreased from 0.99 and 1.01 to 0.96 (P<0.05) and 0.94 (P<0.05). We suppose these changes mainly reflect changes of focal temperature and perfusion of each skeletal muscle.