Vascular and degenerative processes differentially affect regional interhemispheric connections in normal aging, mild cognitive impairment, and Alzheimer disease.
Vascular and degenerative processes differentially affect regional interhemispheric connections in normal aging, mild cognitive impairment, and Alzheimer disease.
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DOI：
10.1161/strokeaha.110.582163
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发表时间：
2010-08
期刊：
影响因子：
8.3
通讯作者：
DeCarli C
中科院分区：
文献类型：
--
作者：
Lee DY;Fletcher E;Martinez O;Zozulya N;Kim J;Tran J;Buonocore M;Carmichael O;DeCarli C
尽管胼胝体(CC)对大脑半球之间的连接至关重要，但关于退行性和血管过程对CC微结构完整性的区域性变化的独立贡献，人们知之甚少。在这里，我们研究了患有轻度认知障碍(MCI)、阿尔茨海默病(AD)的受试者以及认知正常的老年人的这些变化。我们对47名AD、77名MCI和107名认知正常受试者进行了三维磁共振扩散张量成像，并计算了四个CC区对应的四个皮质灰质(GM)同源区域的平均分数各向异性(FA)值。为了评估血管和退变过程，我们还测量了相应区域的皮质GM和白质高强度(WMH)体积，并评估了它们的血管风险。我们发现，在所有三个诊断组中，前部和后部的GM体积与CC相应区域的FA结果显著相关。额叶WMH体积与相应CC区的FA值呈正相关，与GM体积无关，而后方WMH体积与FA值无关。血管风险与大多数CC区域的FA相关，而认知状态的诊断仅与CC前、后区域的FA相关。我们发现，在不同的认知能力范围内，退行性和血管过程以及CC的结构完整性之间存在不同的区域特定关联。基于这些结果，我们提出了一个解释半球间联系的区域分裂的模型。
Despite the critical importance of the corpus callosum (CC) to the connection between brain hemispheres, little is known about the independent contribution of degenerative and vascular processes to regional changes in the microstructural integrity of the CC. Here, we examine these changes in subjects with mild cognitive impairment (MCI), Alzheimer's disease (AD), and in cognitively normal elderly adults. We used three-dimensional brain MRI with diffusion tensor imaging in 47 AD, 77 MCI, and 107 cognitively normal subjects, and calculated mean fractional anisotropy (FA) values for four CC regions corresponding to four homologous regions of cortical gray matter (GM). To assess vascular and degenerative processes, we also measured cortical GM and white matter hyperintensity (WMH) volume in corresponding regions, along with evaluation of their vascular risk. We found that GM volume in anterior and posterior regions was significantly related to FA findings in the corresponding regions of the CC for all three diagnostic groups. Independent of GM volume, frontal WMH volume was also associated with FA values in the corresponding CC regions, but posterior WMH volume was not. Vascular risk was associated with FA of most CC regions, while diagnosis for cognitive state was associated only with FA of the anterior and posterior CC regions. We found differential region-specific associations between degenerative and vascular processes and the structural integrity of the CC across the spectrum of cognitive ability. Based on these results, we propose a model to explain regional disruption in the interhemispheric connection.