论文部分内容阅读
Measuring molecular diffusion has been used to characterize the properties of living organisms.Currently,magnetic resonance imaging(MRI)is the only imaging method that is able to map molecular diffusion in vivo and noninvasively.Traditional diffusion MRI theory is based on the classical Brownian motion model.Recent studies has indicated that a fractional motion(FM)is a more appropriate model to describe anomalous diffusion phenomenon in crowded environment,such as living cells.A general formulation of the FM-based NMR signal under the influence of arbitrary magnetic field gradient waveforms will be introduced in this talk.An explicit analytic solution of the stretched exponential decay format for NMR signals with finite-width Stejskal-Tanner bipolar pulse magnetic field gradients will be show presented.Results of in vivo diffusion-weighted brain images based on FM model will be illustrated,and the resulting parametric maps exhibit remarkable contrasts between different brain tissues will also be presented.