Heterogeneous diffusivity changes within human stroke lesions measured with oscillating gradient spin echo diffusion MRI

Abstract

Short diffusion time oscillating gradient spin echo (OGSE) showed less water diffusion reduction in acute human stroke lesions (n=28) than the typical clinically used long diffusion time pulsed gradient spin echo (PGSE) method. The diffusion time dependency is far greater in ischemic lesions, particularly white matter, than in contralateral healthy brain. These effects were heterogeneous across the lesion with larger OGSE-PGSE differences in regions indicative of larger axons. The range of MD decrease in lesions across patients as measured with OGSE and PGSE showed a linear correlation and is consistent with concomitant axon beading and swelling implied from prior simulations.