No abstract

After femoral artery ligation, the diffusion-tensor indexes changed dynamically in association with the severity and location of muscle damage.

Diffusion tensor imaging (DTI) is frequently applied to characterize the microscopic geometrical properties of tissue. To establish whether and how diffusion MRI responds to transient ischemia of skeletal muscle, we studied the effects of ischemia and reperfusion using DTI and T 2 -weighted MRI before and during ischemia and up to 24 hr after reperfusion. Ischemia was induced by 50 min of hindlimb occlusion with or without dorsal flexor stimulation. During ischemia the apparent diffusion coefficient (ADC) tended to decrease (up to 15%), whereas the fractional anisotropy (FA) and T 2 showed a varied response depending on the protocol and muscle type. During reperfusion the ADC and T 2 initially increased and subsequently renormalized for the occlusion protocol. For the occlusion plus stimulation (OS) protocol, the FA was decreased by 13% and the ADC and T 2 were increased by 20% and 57%, respectively, after 24 hr in the stimulated muscle complex. In the latter tissue the three DTI eigenvalues gradually increased upon reperfusion. The smallest eigenvalue (