Cerebral cortical microinfarcts (CMIs) are a novel MRI marker of cerebrovascular disease (CeVD) that predicts accelerated cognitive decline. Presence of CMIs is known to be associated with global cortical atrophy, although the mechanism linking the two is unclear. Our primary objective was to examine the relation between CMIs and cortical atrophy and to establish possible perilesional atrophy surrounding CMIs. Our secondary objective was to examine the role of cortical atrophy in CMI-associated cognitive impairment.

Patients were recruited from 2 Singapore memory clinics between December 2010 and September 2013 and included if they received the diagnosis no objective cognitive impairment, cognitive impairment (with or without a history of stroke), or Alzheimer or vascular dementia. Cortical thickness, chronic CMIs, and MRI markers of CeVD were assessed on 3T MRI. Patients underwent cognitive testing. Cortical thickness was compared globally between patients with and without CMIs, regionally within individual patients with CMIs comparing brain regions with CMIs to the corresponding contralateral region without CMIs, and locally within individuals patients in a 50-mm radius of CMIs. Global cortical thickness was analyzed as mediator in the relation between CMI and cognitive performance.

Of the 238 patients (mean age 72.5 years, SD 9.1 years) enrolled, 75 had ≥1 CMIs. Patient with CMIs had a 2.1% lower global cortical thickness (B = –0.049 mm, 95% confidence interval [CI] 0.091 to –0.007, p = 0.022) compared to patients without CMIs, after correction for age, sex, education, and intracranial volume. In patients with CMIs, cortical thickness in brain regions with CMIs was 2.2% lower than in contralateral regions without CMIs (B = –0.048 mm [95% CI –0.071 to –0.026], p < 0.001). In a 20-mm radius area surrounding the CMI core, cortical thickness was lower than in the area 20 to 50 mm from the CMI core (mean difference –0.06 mm [–0.10 to –0.02], p = 0.002). Global cortical thickness was a significant mediator in the relationship between CMI presence and cognitive performance as measure with the Mini-Mental State Examination (B = –0.12 [–0.22 to –0.01], p = 0.025).

We found cortical atrophy surrounding CMIs, suggesting a perilesional effect in a cortical area many times larger than the CMI core. Our findings support the notion that CMIs affect brain structure beyond the actual lesion site.

脑皮质微梗死 (CMI) 是脑血管疾病 (CeVD) 的一种新型 MRI 标志物，可预测认知能力加速下降。已知 CMI 的存在与整体皮质萎缩有关，尽管将两者联系起来的机制尚不清楚。我们的主要目标是检查 CMI 和皮质萎缩之间的关系，并确定 CMI 周围可能的病灶周围萎缩。我们的次要目标是检查皮质萎缩在 CMI 相关认知障碍中的作用。

患者在 2010 年 12 月至 2013 年 9 月期间从 2 家新加坡记忆诊所招募，如果他们接受诊断为无客观认知障碍、认知障碍（有或没有中风史）或阿尔茨海默病或血管性痴呆，则纳入这些患者。在 3T MRI 上评估了 CeVD 的皮质厚度、慢性 CMI 和 MRI 标志物。患者接受了认知测试。皮质厚度在有和没有 CMI 的患者之间进行全球比较，在有 CMI 的个体患者中进行区域比较，比较有 CMI 的大脑区域与没有 CMI 的相应对侧区域，以及在 50 毫米半径 CMI 的个体患者中局部的皮质厚度。整体皮质厚度被分析为 CMI 和认知表现之间关系的中介。

在入组的 238 名患者（平均年龄 72.5 岁，SD 9.1 岁）中，75 名 CMI ≥1。在校正年龄、性别、教育和颅内容积。在有 CMI 的患者中，有 CMI 的脑区皮层厚度比没有 CMI 的对侧区域低 2.2%（B = –0.048 mm [95% CI –0.071 至 –0.026]，p < 0.001）。在 CMI 核心周围 20 mm 半径区域，皮质厚度低于 CMI 核心 20 至 50 mm 区域（平均差 –0.06 mm [–0.10 至 –0.02]，p= 0.002)。整体皮层厚度是 CMI 存在与认知表现之间关系的重要中介，通过简易精神状态检查 (B = –0.12 [–0.22 to –0.01], p = 0 . 025)。

我们发现 CMI 周围的皮质萎缩，表明皮质区域的病灶周围效应比 CMI 核心大许多倍。我们的研究结果支持 CMI 影响实际病变部位以外的大脑结构的观点。