Department of Neurology, Medical University of Graz, Graz, Austria.
Panminerva Med. 2012 Sep;54(3):149-60.
Cerebral microbleeds (CMBs) are frequent findings in MRI scans of elderly subjects. Depending on the MRI protocols applied 4.7% to 24.4% of community-based subjects show incidental CMBs. The rates reported for various types of ischemic strokes and intracerebral hemorrhages vary between 19.4% and 68.5%. Most studies also demonstrated CMBs in approximately one third of Alzheimer cases. A lobar distribution of CMBs is considered to relate to cerebral amyloid angiopathy, while CMBs located in the basal ganglia or in infratentorial brain regions are thought to relate to hypertensive vasculopathy. Besides age, hypertension, diabetes mellitus, and low serum cholesterol have so far been identified as risk factors for CMBs. Presence of an APOE ε4 allele is the only genetic factor that was consistently shown to increase the risk for CMB development. There are only few longitudinal studies on the predictive value of CMBs. For incident ischemic strokes and intracerebral hemorrhages hazard ratios of 4.48 and 50.2 have been reported. CMBs also doubled the risk for conversion to dementia in MCI patients, and there are indications for CMBs being possible predictors of increased mortality. Given the small number of longitudinal investigations with often small sample sizes the role of CMBs as predictors of disease needs to be further elucidated. CMBs were significantly more common in warfarin-treated stroke patients who developed intracerebral hemorrhages (ICH). These data are cross-sectional. They do not provide enough evidence to consider CMBs as a contraindication for antithrombotic agents in primary and secondary stroke prevention. CMBs are likely to unfavourably affect cognitive functioning. It remains to be determined if direct lesion-related effects are responsible for this finding or if CMBs are sole markers of more extensive tissue damage in the wake of cerebral small vessel disease leading to widespread visible but also non-visible tissue destruction with a high likelihood for cognitive consequences.
脑微出血 (CMBs) 是老年患者 MRI 扫描中的常见发现。根据应用的 MRI 方案，4.7%至 24.4%的社区人群存在偶发性 CMBs。各种类型的缺血性卒中和脑出血的报告率在 19.4%至 68.5%之间。大多数研究还表明，约三分之一的阿尔茨海默病患者存在 CMBs。CMBs 的叶分布被认为与脑淀粉样血管病有关，而位于基底节或幕下脑区的 CMBs 则被认为与高血压性血管病有关。除了年龄、高血压、糖尿病和低血清胆固醇外，迄今为止，CMBs 的危险因素还包括 APOE ε4 等位基因。目前仅有少数关于 CMBs 预测价值的纵向研究。对于新发缺血性卒中和脑出血，风险比分别为 4.48 和 50.2。CMBs 也使 MCI 患者向痴呆转化的风险增加了一倍，并且有迹象表明 CMBs 可能是死亡率增加的预测因素。由于纵向研究数量较少，且样本量通常较小，CMBs 作为疾病预测因素的作用仍需进一步阐明。在接受华法林治疗的脑出血 (ICH) 患者中，CMBs 更为常见。这些数据是横断面的。它们没有提供足够的证据将 CMBs 视为一级和二级卒中预防中抗血栓药物的禁忌症。CMBs 可能会对认知功能产生不利影响。尚不确定直接与病变相关的影响是否是造成这一发现的原因，或者 CMBs 是否只是脑小血管病后广泛可见但也不可见的组织损伤的标志物，导致广泛的组织破坏，并极有可能导致认知后果。
