Liu Chengxia, Shi Lin, Zhu Wenhao, Yang Shiqi, Sun Pan, Qin Yuanyuan, Tang Xiangyu, Zhang Shun, Yao Yihao, Wang Zhenxiong, Zhu Wenzhen, Wang Defeng
Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
Front Neurosci. 2020 Feb 12;14:83. doi: 10.3389/fnins.2020.00083. eCollection 2020.
Abnormal structural connectivity of cerebral small-vessel disease (CSVD) is associated with cognitive impairment. But the different characteristics of structural connectivity have not been elucidated in early CSVD patients. The current study aimed to investigate the potential differences of structural connectivity in CSVD patients with mild cognitive impairment (MCI) and CSVD patients with normal cognition. Twenty-two CSVD patients with MCI, 34 CSVD patients with normal cognition, and 35 controls, who were age, sex, and education matched underwent diffusion tensor imaging and high resolution T1-weighted imaging. Clinical characteristics, lacunar infarct volume, white matter hyperintensity (WMH) volume, and global atrophy were quantitatively evaluated. Maps of fiber connectivity density (FiCD) were constructed and compared across groups in vertex levels. Pearson correlation was used to estimate the imaging-clinical relationships with control of general characteristics. CSVD patients with MCI had higher lesion load of WMH and lacunar infarcts, and correspondingly lower global FiCD value than CSVD patients with normal cognition ( < 0.01). Lacunar infarct ( = -0.318, < 0.01) and WMH ( = -0.400, < 0.01), but not global atrophy, age, or sex, were significantly correlated with the global FiCD value. CSVD patients with normal cognition showed decreased FiCD value mainly in the prefrontal areas ( < 0.01 with Monte Carlo correction). Compared with CSVD patients with normal cognition, CSVD patients with MCI showed significantly decreased FiCD value in enlarged frontal and parietal areas ( < 0.01 with Monte Carlo correction). Inter-group comparisons showed regional enhanced impairment of connectivity density in CSVD patients with MCI in the left superior frontal gyrus, the left precuneus, and the orbital part of the right inferior frontal gyrus ( < 0.01 with Monte Carlo correction). Regional FiCD value of frontal and parietal areas was associated with the cognitive function ( < 0.01). In conclusion, cognitively normal CSVD patients already have disruptions of structural connectivity. The extent and intensity of connectivity disruptions in frontal and parietal areas may underlie the mechanism of cognitive impairment in CSVD. Fiber connectivity density measurements may be helpful for quantitative description of structural cortical connectivity.
脑小血管病（CSVD）的异常结构连接与认知障碍相关。但早期CSVD患者结构连接的不同特征尚未阐明。本研究旨在探讨轻度认知障碍（MCI）的CSVD患者和认知正常的CSVD患者在结构连接方面的潜在差异。22例MCI的CSVD患者、34例认知正常的CSVD患者以及35例年龄、性别和教育程度相匹配的对照者接受了扩散张量成像和高分辨率T1加权成像。对临床特征、腔隙性梗死体积、白质高信号（WMH）体积和全脑萎缩进行了定量评估。构建了纤维连接密度（FiCD）图，并在顶点水平上对各组进行比较。采用Pearson相关性分析评估成像与临床特征之间的关系，并对一般特征进行控制。与认知正常的CSVD患者相比，MCI的CSVD患者WMH和腔隙性梗死的病变负荷更高，相应地全脑FiCD值更低（<0.01）。腔隙性梗死（=-0.318，<0.01）和WMH（=-0.400，<0.01），而非全脑萎缩、年龄或性别，与全脑FiCD值显著相关。认知正常的CSVD患者主要在前额叶区域FiCD值降低（经蒙特卡洛校正后<0.01）。与认知正常的CSVD患者相比，MCI的CSVD患者在扩大的额叶和顶叶区域FiCD值显著降低（经蒙特卡洛校正后<0.01）。组间比较显示，MCI的CSVD患者在左侧额上回、左侧楔前叶和右侧额下回眶部的连接密度区域损伤增强（经蒙特卡洛校正后<0.01）。额叶和顶叶区域的局部FiCD值与认知功能相关（<0.01）。总之，认知正常的CSVD患者已经存在结构连接中断。额叶和顶叶区域连接中断的程度和强度可能是CSVD认知障碍机制的基础。纤维连接密度测量可能有助于定量描述皮质结构连接。
