Statistical model for diffusion attenuated MR signal.
A general statistical model that can describe a rather large number of experimental results related to the structure of the diffusion-attenuated MR signal in biological systems is introduced. The theoretical framework relies on a phenomenological model that introduces a distribution function for tissue apparent diffusion coefficients (ADC). It is shown that at least two parameters--the position of distribution maxima (ADC) and the distribution width (sigma)--are needed to describe the MR signal in most regions of a human brain. A substantial distribution width, on the order of 36% of the ADC, was found for practically all brain regions examined. This method of modeling the MR diffusion measurement allows determination of an intrinsic tissue-specific ADC for a given diffusion time independent of the strength of diffusion sensitizing gradients. The model accounts for the previously found biexponential behavior of the diffusion-attenuated MR signal in CNS.
Yablonskiy
Dmitriy A
DA
Department of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. Yablonskiy@mir.wustl.edu
Bretthorst
G Larry
GL
Ackerman
Joseph J H
JJ
D001921:Brain / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D015233:Models, Statistical