目的 · 明确脑微出血（CMBs）对于 SVD 早期认知障碍的影响及其作用机制。方法 · 连续招募严格定义的 SVD 非痴呆患者 57 名，对其进行详细神经心理测查，并对患者进行磁敏感成像（SWI）和弥散张量成像（DTI）磁共振检查。根据 CMBs 计数将患者分 为 CMBs 组、非 CMBs 组，以及多发性 CMBs 组（全脑 CMBs ≥ 3 个）、非多发性 CMBs 组（全脑 CMBs<3 个）。用感兴趣区分析法 测定脑室旁、半卵圆中心和皮质下总的白质平均弥散度（MD）和各向异性分数（FA）。 结果 · 多发性 CMBs 组在注意执行和记忆功 能的评分显著低于非多发性 CMBs 组。全脑 CMBs 计数与脑室旁白质 MD、皮质下白质 MD、脑室旁白质 FA 和皮质下白质 FA 均显 著相关。全脑 CMBs 计数经矫正后与注意执行功能显著相关，进一步经皮质下 / 脑室旁白质 FA 和 MD 及 CMBs 部位矫正后仍显著相 关。结论 · CMBs 能反映 SVD 患者缺血性病变导致的白质完整性破坏程度，并独立作用于脑实质损伤而造成早期认知障碍；CMBs 对 认知损害的作用可能存在阈值效应。

 Objective · To make clear the role of cerebral microbleeds (CMBs) for early cognitive impairment in small vessel disease (SVD).  Methods · Fifty-seven consecutive SVD patients without dementia were strictly recruited. All participants were examined with a comprehensive battery of neuropsychological tests, SWI and DTI. According to the amount of CMBs, the patients were divided into CMBs group and non-CMBs group, or divided into multiple CMBs group (CMBs ≥ 3) and non-multiple CMBs group (CMBs<3). The mean diffusivity (MD) and fractional anisotropy (FA) in periventricular, central semiovale and subcortical white matter was analyzed with a region-of-interest method.  Results · The score of multiple CMBs group in attention and memory function was significantly lower than that of the non-multiple CMBs group. Correlation analysis showed that the count of CMBs in the whole brain was significantly correlated with periventricular white matter MD, subcortical white matter MD, periventricular white matter FA and subcortical white matter FA. The count of CMBs in the whole brain adjusted by age, gender, education was significantly correlated with attention/ executive function. After adjustment of subcortical/ periventricular white matter FA and MD and locations of CMBs they still had significant correlation.  Conclusion · CMBs can reflect the degree of destruction of white matter integrity, and have independent effects on injury of brain parenchyma, resulting in early cognitive impairment. The research also suggests the role of CMBs in cognitive impairment may exist threshold value effect.