大脑中动脉狭窄与其深穿支供血区单发脑梗死的关系

目的 分析大脑中动脉(MCA)深穿支供血区单发脑梗死的形态学表现,进一步探讨其与MCA狭窄的关系.方法 连续入选2005年1月至2006年12月于北京协和医院神经科住院治疗急性脑梗死,并经头颅DWI检查明确急性梗死灶为单发,且位于MCA深穿支供血区域的55例患者;所有患者均行TCD和MRA检查,颅外颈内动脉狭窄>50%以及有可疑心源性栓子来源的患者从研究中排除.根据是否存在病灶同侧MCA狭窄将入选患者分为两组:MCA狭窄组(14例)与MCA正常组(41例).测量DWI上急性梗死灶的直径、面积和体积,并将直径≤2 cm归为经典腔隙性梗死,直径>2 cm归为纹状体内囊梗死.DWI上的梗死灶区分为基底节区、侧脑室体旁和同时累及上述2个部位,并判断MRI T2>像上皮质下多发陈旧性小梗死灶或白质疏松是否存在.结果 55例患者中,病灶侧MCA狭窄患者14例(25.5%),MCA正常患者41例(74.5%).MCA狭窄组中经典腔隙性梗死占71.4%,MCA正常组中经典腔隙性梗死占67.3%,差异无统计学意义(χ2=0.147,P=0.701).MCA狭窄组与正常组患者MCA深穿支梗死病灶的大小(包括直径、面积及体积)差异均无统计学意义.MCA正常组和MCA狭窄组病灶在基底节区、侧脑室体旁及基底节区+侧脑室体旁分布的比例依次为:正常组31.7%、17.1%和51.2%;狭窄组35.7%、28.6%和35.7%,两组间差异无统计学意义(χ2=1.272,P=0.529).同时存在皮质下多发陈旧性小梗死灶或白质疏松的患者在MCA正常组有23例(56.1%),在MCA狭窄组有3例(21.4%),二者差异有统计学意义(χ2=5.033,P=0.025).结论 MCA深穿支供血区梗死具有不同的发病机制,MCA狭窄和穿支动脉本身病变均可造成深穿支供血区单发脑梗死.梗死灶的大小、体积及梗死发生的部位与是否存在同侧大脑中动脉狭窄无明显相关性,而同时存在皮质下多发陈旧性小梗死灶或白质疏松对穿支动脉病变有提示作用.

Association between middle cerebral artery and it's single infarction in the territory of perforating arteries

Objective To analyze the morphologic characteristics of the single infarct in the territory of perforating arteries which arise from the middle cerebral artery (MCA),and further to investigate the association between the type of cerebral infarction and the isolated stenotic disease of the ipsilateral MCA.Methods Fifty-five patients with acute ischemic stroke who were admitted to the Department of Neurology,Peking Union Medical College Hospital,Beijing,China during January 1,2005 and December 31,2006 were identified.All of the patients had a single acute infarction in the territory of the MCA perforating arteries revealed on diffusion weighted imaging (DWI).Transcranial Doppler (TCD) and magnetic resonance angiography (MRA) were performed for all patients.Patients with stenesis >50% of proximal internal carotid artery and potential cardiac sources of embolism were excluded from the study.Patients were classified into 2 groups according to the presence of the atberosclerotic stenosis of the ipsilateral MCA: patients with or without MCA stenosis.Size of the lesions was measured including the diameter,area and volume.The infarcts with a diameter less than 2 cm were classified as lacunar infarcts; those bigger than 2 cm were classified as the striatocapsular infarcts.The infarcts on DWI was seen in basal ganglia,the body of lateral ventricle and beth.The concomitance of subcortical multiple small old infarcts or leucoariosis on T2>WI-MRI between the two groups was assessed.Results Among these 55 patients,14 (25.5%) had stenosis of the ipsilateral MCA and 41 (74.5%) had a normal MCA.In the group of MCA stenosis,71.4% patients were lacunar infarcts; 67.3% patients were also lacunar infarcts in the normal MCA group.There was no significant difference between the two groups (χ2=0.147,P=0.701).No significant difference in the diameter,area and vo|ume of the infarcts was found between the two groups.The basal ganglia,the body of lateral ventricle and both of these places involvement accounted for 31.7% ,17.1%,51.2% in the normal MCA group; 35.7%,28.6%,35.7% in the stenotic MCA group.No significant difference was found (χ2=1.272,P=0.529).Twenty-three (56.1%) patients had concomitant of small old subcortical multiple infarcts or leucoariosis in the normal MCA group and 3 (21.4%) in the MCA stenosis group,and there was a significant difference between the two groups(χ2=5.033,P=0.025).Conclusions A series of pathologic mechanisms are supposed to cause the single infarction in the territory of MCA perforating arteries.Stenosis of MCA is an underlying cause in addition to perforating artery diseases.There is no significant difference in the size,volume or distribution of the lesions between the two groups.The concomitant of subcortical multiple small old infarcts or leucoariosis may demonstrate the perforating artery disease.