Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Hemodial Int. 2024 Apr;28(2):178-187. doi: 10.1111/hdi.13133. Epub 2024 Feb 13.
Hemodialysis patients have increased white matter and gray matter pathology in the brain relative to controls based on MRI. Diffusion tensor imaging is useful in detecting differences between hemodialysis and controls but has not identified the expected longitudinal decline in hemodialysis patients. In this study we implemented specialized post-processing techniques to reduce noise to detect longitudinal changes in diffusion tensor imaging parameters and evaluated for any association with changes in cognition.
We collected anatomical and diffusion MRIs as well as cognitive testing from in-center hemodialysis patients at baseline and 1 year later. Gray matter thickness, white matter volume, and white matter diffusion tensor imaging parameters were measured to identify longitudinal changes. We analyzed the diffusion tensor imaging parameters by averaging the whole white matter and using a pothole analysis. Eighteen hemodialysis patients were included in the longitudinal analysis and 15 controls were used for the pothole analysis. We used the NIH Toolbox Cognition Battery to assess cognitive performance over the same time frame.
Over the course of a year on hemodialysis, we found a decrease in white matter fractional anisotropy across the entire white matter (p < 0.01), and an increase in the number of white matter fractional anisotropy voxels below pothole threshold (p = 0.03). We did not find any relationship between changes in whole brain structural parameters and cognitive performance.
By employing noise reducing techniques, we were able to detect longitudinal changes in diffusion tensor imaging parameters in hemodialysis patients. The fractional anisotropy declines over the year indicate significant decreases in white matter health. However, we did not find that declines in fractional anisotropy was associated with declines in cognitive performance.
基于 MRI，与对照组相比，血液透析患者的大脑白质和灰质病变明显增加。弥散张量成像（DTI）在检测血液透析与对照组之间的差异方面很有用，但尚未确定血液透析患者预期的纵向下降。在这项研究中，我们实施了专门的后处理技术来减少噪声，以检测弥散张量成像参数的纵向变化，并评估其与认知变化的任何关联。
我们在基线和 1 年后收集了中心血液透析患者的解剖和弥散 MRI 以及认知测试。测量灰质厚度、白质体积和白质弥散张量成像参数，以识别纵向变化。我们通过平均整个白质和使用坑洼分析来分析弥散张量成像参数。18 名血液透析患者被纳入纵向分析，15 名对照者被纳入坑洼分析。我们使用 NIH 工具包认知电池在相同的时间框架内评估认知表现。
在血液透析的一年中，我们发现整个白质的白质分数各向异性下降（p<0.01），并且低于坑洼阈值的白质分数各向异性体素数量增加（p=0.03）。我们没有发现整个大脑结构参数变化与认知表现之间的任何关系。
通过采用降噪技术，我们能够检测到血液透析患者弥散张量成像参数的纵向变化。一年中分数各向异性的下降表明白质健康状况显著下降。然而，我们没有发现分数各向异性的下降与认知表现的下降有关。
