BACKGROUND Since the advent of magnetic resonance imaging technology, cerebral microbleeds can be diagnosed in vivo. However, the underlying mechanism of cerebral microbleed formation is not fully understood. OBJECTIVES This study aimed to identify the factors associated with cerebral microbleeds after carotid artery stenting (CAS). METHOD We retrospectively examined 125 patients who underwent CAS for carotid stenosis. Cerebral microbleeds were investigated using T2*-weighted gradient-echo (GRE) imaging before and after CAS. We analyzed the possible association of new microbleeds with the following risk factors: the number of baseline microbleeds and ischemic cerebral lesions, the occurrence of cerebral hyperperfusion syndrome, and new ischemic cerebral lesions after CAS. RESULTS Baseline cerebral microbleeds were detected in 53 patients (42.4%). New cerebral microbleeds after CAS were observed in 13 of 125 patients (10.4%) and were exclusively associated with new ischemic lesions but not with other risk factors. No patient showed a merged image of a new cerebral microbleed on GRE imaging or a new ischemic lesion on diffusion-weighted imaging. Lobar and deep microbleeds were noted in 12/13 (92.3%) and 1 patient (7.7%), respectively. Of 12 patients with new microbleeds, 10 (76.9%) and 2 (15.4%) had a new microbleed in the ipsilateral and contralateral hemispheres, respectively. CONCLUSIONS We found that new cerebral microbleeds developed after CAS and that these might be associated with new ischemic lesions, mostly in the territory of the treated carotid artery. We speculate that these microbleeds result from the deoxygenation of hemoglobin in the embolus or, alternatively, small hemorrhagic transformation of ischemic lesions.

中文翻译：

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颈动脉支架置入术后微出血：小栓塞可诱发脑微出血。

背景技术由于磁共振成像技术的出现，可以在体内诊断出脑微出血。但是，脑微出血形成的潜在机制尚未完全了解。目的本研究旨在确定颈动脉支架置入术（CAS）后与脑微出血相关的因素。方法我们回顾性检查了125例行CAS的颈动脉狭窄患者。在CAS之前和之后，使用T2 *加权梯度回波（GRE）成像研究了脑微出血。我们分析了新的微出血与以下危险因素的可能关联：基线微出血和缺血性脑病变的数目，脑灌注异常的发生以及CAS后新发的缺血性脑病变。结果在53例患者中发现了基线脑微出血（42。4％）。125例患者中有13例（10.4％）观察到CAS后出现新的脑微出血，并且仅与新发的缺血性病变有关，而与其他危险因素无关。没有患者在GRE成像上显示新的脑微出血的合并图像，或在扩散加权成像上显示新的缺血性病变。大叶和深层微出血分别在12/13（92.3％）和1例患者（7.7％）中发现。在12例新的微出血患者中，分别有10例（76.9％）和2例（15.4％）在同侧和对侧半球有新的微出血。结论我们发现CAS后出现了新的脑微出血，这些出血可能与新的缺血性病变有关，主要在经治疗的颈动脉内。我们推测这些微出血是由栓子中血红蛋白的脱氧引起的，或者是