Preliminary Clinical Application Of DTI In Studying Normal Adult Brain And Cerebral Infarction

OBJECTIVE â‘ To study the diffusion anisotropic features of white matter fibers of normal adult brain by using MR diffusion tensor imaging (DTI).â‘¡To evaluate the value of DTI in diagnosing cerebral infarction. MATERIALS and METHODS Diffusion tensor images were obtained from 26 volunteer who underwent clinical MR imaging and were found to have no abnormalities on conventional MR images and 35 patients who were clinically diagnosed cerebral infarction or Conventional MR images showed infarction lesions. Color-coded FA images and three-dimensional color-coded tensor images were reconstructed. For volunteers, fractional anisotropy (FA) were measured in some main white matter structures of peripheral white matter, basal ganglia, cerebral peduncle etc. For infarction patients, average apparent diffusion coefficient (ADCAV) and fractional anisotropy were measured and compared between infarction lesions and corresponding contralateral normal regions. RESULTS In normal volunteers group, anisotropy measurements in white matter regions were significantly larger than that of gray matter regions, different white matter structures show different anisotropy degree, with the commissural neurofibers of white matter(corpus callosum) having the highest value, followed by projection fibers(internal capsule) and association fibers(centerum semiovale). Reconstruction FA images and three-dimensional color-coded tensor images can display main white matter fibers. In infarction patients group,DTI can early detect some small infarction lesions in white matter. With the pathophysiological evolution of the disease, FA and ADCAV changes regularly. In hyper-acute stroke, FA of lesions have no consistent change, appreciably elevated or decreased. In acute, sub-acute and chronic stages of cerebral infarction, FA of lesions unrecovered declined. Change in ADCAV had tendency which appear reduced obviously, elevated, renormalized, increased. CONCLUSION DTI can precisely showed the orientation and distribution of cerebral white matter fiber tracts, providing a valuable examination to study the relationship between cerebral functions and white matter fiber crossings. Combining FA and ADCAV will be helpful in assessing the onset time and precisely staging the cerebral infarction. Compare with conventional MR images and DWI, DTI can show spatial relationships between the white matter fiber tract and the infarction and can improve the anatomic definition of lesion localization.