Preliminary Study on Diffusion Tensor Imaging Characteristics of Cerebral White Matter Fibers Anisotropy in Acute Cerebral Infaction

Objective:Using MR diffusion tensor imaging (DTI) to study the anisotropic characteristics of cerebral white matter fibers in healthy volunteers and patients with acute cerebral ischemic stroke.Methods:17 patients with acute cerebral ischemic stroke and 16 healthy volunteers had MRI T1WI、T2WI sequences and diffusion weighted imaging (DWI) as well as diffusion tensor imaing (DTI).DTI data were post-processed with volume one 1.64 and dTVII-R1 software,fractional anisotropy (FA) maps、directionally encoded color (DEC) maps of all patients were acquired.For volunteers,FA values were measured in the selected region of interest (ROI) within capsula interna,corpus callosum and centrum semiovale.For patients having infarct,FA values were measured in the infarct area and the contra-lateral normal white matter region.Results:Main cerebral white matter fibers could be displayed on reformatted FA and DEC maps.In healthy volunteers,the FA values varied in different regions of white matter.No significant difference existed in the FA values of bilateral cerebral white matter regions.In patients with superacute stroke,the FA value of white matter could be slightly increased or decreased when compared with the contra-lateral.In patients with acute stroke,the FA value in infarct area of white matter was obviously lower than that in normal contra-lateral hemisphere with significant statistical difference (t=10.987,P0.01).The percentage of decrease of FA value in acute infarct region has significant positive correlation with the time of attack (r=0.841,P0.05).Conclution:The orientation and distribution of cerebral white matter fiber tracts could be precisely showed on DTI.The orientation and degree of anisotropy changes of white matter fiber in infarct area could be displayed on FA maps and DEC maps.In the acute stage of ischemic stroke,the percentage of decrease of FA value within infarcts increased according to the prolongation of disease,which might reflect the course of the stroke.