Biexponential diffusion attenuation in the rat spinal cord: computer simulations based on anatomic images of axonal architecture.

摘要: Water diffusion in neurological tissues is known to possess multicomponent behavior. The fractions of fast and slow apparent components have often been attributed the volume extracellular space (ECS) intracellular (ICS) although are at variance with tissue compartment ratios. In this article puzzle was examined a finite difference simulation model on basis optical images from sectioned rat spinal cord. Here results show that assignment obtained biexponential fits attenuation ECS ICS ratios not correct. Rather, observed behavior caused by motional restriction limited intercompartmental water exchange long times shown become monoexponential. Although measured also depend T2 relaxation time protons various compartments, sensitivity small thus differences unlikely explain mismatch between cellular fractions. Magn Reson Med 47:455–460, 2002. © 2002 Wiley-Liss, Inc.