The Effect of age, gender and type 2 diabetes mellitus in cerebral white matter integrity
Date Issued
2013
Date
2013
Author(s)
Hsu, Jung-Lung
Abstract
Cerebral white matter (WM) stands the same important role as well as the gray matter (GM) in the cerebral function. Cerebral WM is constructed by the neuronal fiber bundles which connent with various brain regions and modulate the different functions. In the past, image study for cerebral WM was focused on the volumetric changes (e.g. tissue loss) or intensity changes (e.g. white matter hyperintensity, WMH). However, these two indexes neither sensitive to the lesion detection nor loss the detail anatomic structural labeling. Recently developed magnetic resonance (MR) diffusion tensor imaging (DTI) technique could provide the more dedicate anatomical fiber bundle labeling, which could help the researcher in accurate anatomical localization. It also could provide more detail micro-structural information then previously conventional MR technique in WM. In this study, we use the DTI to study the effects of age, gender and vascular risk factors in cerebral WM.
In the first part of thesis, we summarized the effect of age, gender and vascular risk factors in cerebral WM based on the volumetric studies and WMH from literatures. Then, a brief description of DTI technique and application was followed.
In the second part of thesis, we present three papers regarding age, gender and type 2 DM and cerebral WM.
1. In chapter 4, we used the linear regression model to study the age and gender effect on WM microsturcture. Our study found that microsturctural integrity base on the DTI parameters in the anterior cingulate gyrus and the anterior/posterior limbs of internal capsule correlated with the aging change. We also found the WM integrity in the right side temporal lobes has the gender difference.
2. In chapter 5, a high-order polynominal regression model to analyze the aging effect on various brain regions. Traditional linear regression model assumed the aging effect could be linear correlate with the variable and the various brain regions. In this study, we found the fractional anisotrophy (FA) index showed a linear decreased with aging change, but the mean diffusivity (MD) showed a quadratic change with aging process. The lowest level of MD value was found at age 44, which could not be found by the linear regression model. The biological interpretation could be that WM integrity could present as accerate changes with age in different brain regions.
3. In chapter 6, we discuss the type 2 DM and WM integrity. Our study found that even the conventional MR showed no significant changes in WM, the type 2DM patient still could have the microsturctural integrity changes based on the DTI findings. Moreover, this change was associated with disease duration.
In summary, DTI provided a useful tool to explore the WM integrity and its relationship with the disease. It also could provide the structural connentivity map for different brain regions. These adventage help researchers to reconstruct a more sophicate brain-function relationship.
Subjects
磁振擴散張量造影
年齡
心血管危險因子
SDGs
Type
thesis
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