Cerebral White Matter Changes In Diffusion Tensor MRI With Aging Brain And Leukoaraiosis

Diffusion tensor imaging (DTI) is highly sensitive to white matter tract and non-invasively provides maps of microscopic structural information of oriented tissue in vivo. It provides a new tool for the white matter maturation and aging process. We observed the quantitative DTI to study the microstructural changes in white matter during normal aging and leukoaraiosis patients in order to provide more helpful information for the clinical management.Part I : The cerebral white matter of normal aging: DTI studyPurpose: We used quantitative DT MR imaging to elucidate changes in apparent diffusion coefficients (DCavg) and fraction anisotropy (FA) during normal aging.Materials and Methods: Diffusion tensor MR imaging was performed in 25 normal aging (14 men, 11 women; age range 60-79 years, mean age 68.5). 30 younger controls (18 men, 12 women; age range, 31-59 years, mean age 37.0). Subjects were examined by neurologic and neuropsychological assessment with MMSE without disorders affecting the central nervous system. DCavg and FA were determined in standard regions of the frontal, parietal white matter, genu, splenium of the corpus callosum and centrum semiovale. The statistic analysis was SPSS software.Results: On DTI, there was no significant difference in DCavg or FA between male and female or between the right and left hemisphere. A significant DCavg increase and FA decline with advancing age was found. Especially DCavg and FA of genu of the corpus callosum and centrum semiovale.Conclusions: Quantitative diffusion tensor analysis correlate with normal aging and may help in assessing normal age-related changes and serve as a standard for comparison with neurodegenerative diseases. Diffusion tensor imaging measurements relationships with cognition may be useful in the cognition decline of normal aging correlations with microstructural changes of white matter.Part II :The cerebral white matter of leukoaraiosis: DTI studyPurpose: The purpose of this study is to find DCavg and FA values of ROI ( regions of interest ) correlating with the degree of the severity of leukoaraiosis (LA). And conventional MRI provides little information about white matter microstrural disruptions and correlates poorly with cognition dysfunction. But DTI may provide better about these.Materials and Methods: Diffusion tensor MR imaging was performed in 55 LA ( 25 healthy subjects with LA and 30 ischamic LA ) and 22 healthy aging with no LA on the conventional MR images. DCavg and FA values were calculated for the regions of NLA ( normal subjects with LA ), ILA (ischamic LA) lesions and normal white matter. LA extension was assessed on T2 weighted images by a semiquantitative visual score. All subjects were checked by neurologist with MMSE and clinical neurologic examination.Results: The more severe the LA was, the higher the DCavg values and thelower FA values of the leukoaraiotic regions became. The significant correlation was identified between normal appearing white matter of DTI and MMSE scores.Conclusions: The regions of LA show characteristic changes in DCavg, FA values. DTI can find microstructural white matter changes not normally seen with conventional MRI and these changes correlates with cognition dysfunction.