Unilateral watershed cerebral infarcts

We studied 51 patients with symptomatic unilateral watershed (WS) cerebral infarct on CT. In 22 patients, the infarct was between the superficial territory of the anterior and middle cerebral arteries, 20 had an infarct between the superficial territory of the middle and posterior cerebral arteries, and 9 had an infarct between the superficial and deep territory of the middle cerebral arteries. Each type had a characteristic neurologic picture. Syncope at onset (37%) and focal limb shaking (12%) were frequent. Thirty-eight patients (75%) had internal carotid artery occlusion or tight stenosis associated with a hemodynamically significant cardiopathy, increased hematocrit, or acute hypotension. Embolic infarction was probable in only two patients (4%) who had only atrial fibrillation.     

Angiographic findings of ischemic stroke in children

A cooperative study was undertaken in the Tohoku district of Japan to investigate the relatively rare phenomenon of cerebral infarction in children. The purpose of the present paper is to describe the cerebral angiographic findings in 48 children whose ischemic lesions were confirmed by CT scan. The majority of lesions were considered to be idiopathic. The areas of cerebral infarction appearing in the CT scans were located in the territory of the middle cerebral artery including the basal ganglia. Angiographical abnormalities were observed in 40 patients (83%). The majority occurred in the supraclinoid portion of the internal carotid artery and in the cisternal portion of the middle and anterior cerebral arteries. Multiple lesions, such as in the C1, A1, and M1 or the C1, M1, and M2 segments were observed in 22 cases. These lesions generally appeared in continuation; no bilateral intracranial lesions were observed. Repeated angiography was performed in 22 cases, and in 55% of these some recovery of the lesions was seen.     

大脑中动脉狭窄脑深部小梗死发病机制的研究

目的 研究大脑中动脉粥样硬化性狭窄患者脑深部小梗死的发生频率和发病机制。方法86例发病时间〈1周的急件脑梗死患者，行经颅多普勒超声、彩色超声、磁共振血管造影及功能磁共振成像等检查方法被明确诊断为症状性大脑中动脉粥样硬化性狭窄，并排除颈内动脉病变、心源性栓塞以及非动脉粥样硬化性狭窄。利用磁共振扩散加权成像观察梗死灶的形态学表现及特点，分析其发病机制。结果37例（43．02％）症状性大脑中动脉粥样硬化性狭窄患者存在深部小梗死，多呈孤立性单发病灶。其中内囊纹状体梗死及巨大腔隙者18例（20．93％），梗死灶体积多超过两个层面，少数病灶呈多灶分布的特点；直径较小的腔隙性梗死19例（22．09％），梗死灶体积〈15mm，多位于一个层面内。伴有大脑中动脉粥样硬化性狭窄的深部小梗死的患者，病情多不稳定，预后较差。所有脑深部小梗死患者均伴有大脑中动脉主干支狭窄，且梗死灶体积与大脑中动脉粥样硬化性狭窄程度有关，内囊纹状体梗死多见于大脑中动脉重度狭窄者。结论约50％大脑中动脉粥样硬化性狭窄患者存在脑深部小梗死，其发病机制与大脑中动脉粥样硬化斑块或斑块残端血栓蔓延堵塞深穿支动脉入口有关。对此类患者的治疗不同于经典的腔隙性脑梗死。     

Serial magnetic resonance images in patient with the middle cerebral artery dissection]

A 30-year-old man suffered from transient left hemiparesis and was admitted under the clinical diagnosis of transient ischemic attack. Cerebral angiogram on admission disclosed severe stenosis at the horizontal portion of the right middle cerebral artery. Magnetic resonance images (MRI) on axial view showed a linear enhanced lesion along the stenosis. Images on sagittal view disclosed a crescent-like lesion surrounding a flow void of the middle cerebral artery. After administration of aspirin, he had never suffered from hemiparesis. The enhanced lesion of the middle cerebral artery gradually disappeared on MRI. Although the middle cerebral artery showed temporary improvement of the stenotic lesion, it finally occluded 9 months after the onset. A diagnosis of spontaneous dissection of the right middle cerebral artery was made. The process of the arterial hemodynamics, such as a shrinking of the pseudo-lumen and a flow improvement in the true lumen, was well documented on serial MRI with Gd-DTPA and serial MRA.     

Weakness of the lower extremity in carotid occlusive disease

Nineteen patients experienced progressive or episodic weakness of one lower extremity caused by severe stenosis or occlusion of the internal carotid artery. The majority of patients (84.2%) had occlusion or severe stenosis at the origin. Based on clinical profiles, angiographic findings, and cerebral blood flow patterns, we concluded that the pathophysiologic mechanism was hypoperfusion in the border zone between the anterior cerebral artery and the middle cerebral artery and that patients with progressive weakness had more extensive compromise in cerebral circulation. Following surgical treatment in 17 patients, progressive and episodic weakness disappeared and the majority of them (76.4%) became asymptomatic. However, the patients with stenosis at the siphon and those with progressive weakness from occlusion at the origin appeared to be at increased risk for cardiac death.     

Occlusive cerebrovascular disease in young adults

13 patients under 40 years of age had cerebral infarction and angiographic evidence of arterial stenosis or occlusion. None of them had cardiac disorders prone to cerebral embolism. Five patients had occlusion at the origin of the internal carotid artery, one had occlusion of the common carotid artery and one each had stenosis at the origin of the internal carotid and common carotid arteries, respectively. Two patients had unilateral occlusion of the supraclinoid portion of the carotid artery with basal collaterals that had some resemblance to the Moyamoya disease. Three patients demonstrated stenosis or occlusion of the middle and/or anterior cerebral arteries. Three patients had hypercholesterolemia, one of whom was hypertensive. None had confirmed diabetes mellitus. One female, who died, had taken oral contraceptives for 3 years. A male, with internal carotid artery occlusion, had serological evidence for syphilis.     

Internal borderzone infarction following acute middle cerebral artery occlusion

In 36 patients suffering acute middle cerebral artery (MCA) occlusion, we studied the angiographic findings within 6 hours of the ictus and the chronic CT results at 3 months. Seven patients suffering distal pial MCA branch occlusion developed a pattern of internal borderzone infarction on follow-up CT. Carotid artery or carotid siphon stenosis or occlusion was absent in all seven. Proximal MCA branch occlusions, prior to the origin of the lenticulostriate arteries, were associated with extensive cortical and deep infarction in the entire MCA territory in 14 patients. There was proximal carotid artery or siphon stenosis or occlusion in 12 of these 14 patients. The remaining 15 patients showed a mixture of proximal and distal MCA occlusions and patchy ischemic damage in the MCA territory. There were no cases of superficial cortical watershed infarction. These data show that internal borderzone infarctions may result from intracranial MCA branch occlusions alone and need not be associated with hemodynamic alterations due to large vessel extracranial disease.     

Clinical implication of cerebral artery calcification on brain CT

BACKGROUND AND PURPOSE: Arterial calcification is a process of atherosclerosis, usually taking place within advanced atheromatous plaque. In the coronary arteries, calcification seen on computed tomography (CT) often indicates severe stenosis, and is noted in almost all patients with coronary symptoms. Calcification of the cerebral arteries is also frequently observed on brain CT, but its clinical significance has yet to be clarified. To evaluate the clinical significance of cerebral arterial calcification on brain CT, we investigated the angiographic and transcranial Doppler ultrasonography (TCD) findings of calcified cerebral arteries. METHODS: The subjects were 57 patients with ischemic stroke, all of whom underwent brain CT, digital subtraction cerebral angiography and TCD. Stroke subtypes were defined according to TOAST classification. Two clinicians who were blinded in respect to the patients' clinical history and to each other's interpretation, determined the presence of cerebral arterial calcification and the degree of angiographic stenosis. RESULTS: Cerebral artery calcification was noted in 23 patients (40%) out of a total of 46 arteries, consisting of 23 internal carotid, 15 vertebral, 5 basilar, 2 middle cerebral and 1 anterior cerebral artery. The patients with calcification were significantly older and more hypertensive than those without calcification. All the patients with calcification showed either large artery atherosclerosis or lacunar stroke. Hemodynamic alterations measured by TCD were rarely observed in calcified arteries. The severity and extent of the atherosclerotic changes were significantly greater in the patients with calcification than those without calcification. CONCLUSION: These results suggest that cerebral arterial calcification does not directly indicate hemodynamically significant atherosclerotic stenosis involving calcified segments, but indicates the underlying etiology of either large artery atherosclerosis or lacunar stroke, and raises the possibility of a diffuse atherosclerotic process being present in the cerebral circulation.     

急性脑梗死散在和单一弥散加权成像病损与其供血动脉狭窄的关系

目的 探讨急性脑梗死弥散加权磁共振成像(DWI)上大脑中动脉(MCA)供血区散在性或单一性缺血性病损与其脑供血动脉狭窄或闭塞的关系.方法 回顾性分析73例连续积累的DWI显示一侧MCA供血区脑梗死的病例,入组病例均排除心源性栓塞性脑梗死,所有患者均在发病24 h内进行MRI和MRA等检查,7例患者并进行DSA.采用DWI急性缺血性病损分类方法 分为散在病损组和单一病损组,比较两组的病灶同侧MCA、颈内动脉(ICA)颅内段和颅外段狭窄或闭塞的发生率.结果 散在病损组42例,单一病损组31例.在病损同侧ICA颅外段和MCA闭塞或重度狭窄方面两组差异有统计学意义(28.6%与0,x2=10.6,P=0.001).在病损同侧ICA颅内段并MCA轻中度狭窄方面,两组间差异具有统计学意义(31.0%与9.7%,x2=4.717,P=0.03).散在病损与MCA和(或)ICA严重或多发狭窄呈正相关(OR值为13.7,95%CI:3.6～52.5).在MRA或DSA未发现颅内外大血管狭窄方面,两组间差异具有统计学意义(11.9%与32.3%,x2=4.526,P=0.033).散在病损组与无明显血管狭窄呈负相关(OR值为0.284,95%CI:0.09～0.94).结论 (1)脑梗死急性期DWI显示的MCA区散在性病损患者,MCA和ICA狭窄、甚至闭塞的可能性较大,以ICA颅外段闭塞较为常见;(2)DWI显示单一病损时提示脑供血动脉狭窄程度较轻,范围较局限,小血管病变的可能性相对较高,很少为严重的ICA颅外段狭窄或闭塞.

Abstract：

Objective To investigate the relationship between scattered or single lesion of acute cerebral infarction in middle cerebral artery territory on diffusion-weighted imaging (DWI) and stenosis of middle cerebral artery (MCA) or internal carotid artery (ICA). Methods With exclusion of cardioembolism, 73 consecutive patients with acute cerebral infarction of the unilateral MCA territory on DWI were analyzed. All patients got magnetic resonance imaging (MRI) and angiography (MRA) within 24 hours after onset, and 7 patients also had digital subtraction angiography (DSA). The patients were classified into single lesion group or scattered lesions group according to the DWI findings. The incidence of stenosis or occlusion of ipsolateral MCA, intracranial and extracranial ICA were compared between the two groups. Results 42 patients had scattered lesions and 31 patients had single lesion. The scattered-lesions group had a high incidence of ipsilateral extracranial ICA or MCA occlusion or severe stenosis ( 25.6%versus 0, x2 = 10.6, P = 0.001 ) and a high incidence of ipsilateral intracranial ICA or MCA moderate or mild stenosis (31.0% versus 9.7% ,x2 =4.717, P =0.03 ). A positive correlation was found between the scattered lesions and severe or multifocal stenosis of ipsilateral ICA and MCA ( OR: 13.7, 95% CI: 3.6 to 52.5). There was a low incidence of absence of extra- and intracranial stenosis on MRA or DSA in the scattered-lesions group ( 11.9% versus 32.3%, x2= 4.526, P = 0.033 ). A negative correlation was found between the scattered lesions and absence of large-artery stenosis ( OR: 0.284, 95% CI: 0.09 to 0.94).Conclusions ( 1 ) Patients with acute cerebral infarction and scattered lesions on DWI were more likely to suffer from stenosis or occlusion of ICA or MCA, especially over the extracranial ICA. (2) Patients with single lesion were less likely to have severe or multiple stenosis of MCA and ICA, indicating the relevance of small-vessel pathogenesis.     

Effect of chronic middle cerebral artery stenosis on the local cerebral hemodynamics

In 36 patients with angiographically proven middle cerebral artery (MCA) stenosis, local cerebral hemodynamics were studied employing angiography, 133Xe inhalation regional cerebral blood flow (rCBF) measurements and CT scans. They had transient ischemic attacks in 8 and completed stroke in 28. The patients with less than 50% stenosis (n = 16) had no hemodynamic abnormality in angiographical and rCBF examinations. The infarction in this group was small and located in the basal ganglia area. The patients with 50 to 74% stenosis (n = 9) often revealed a delayed filling of MCA branches in the angiography, however, they showed no significant rCBF reduction. The infarction in this group was also small and located in the basal ganglia area. The patients with 75 to 99% stenosis (n = 11) exhibited a significant flow depression both in angiographical and rCBF examinations. Three of them had large cerebral infarction in the watershed zone or the cerebral cortex. The results of the present study suggest that the hemodynamic effect of MCA stenosis begins to manifest at 50% in grade and becomes apparent at 75%. The danger of hemodynamic crisis as well as the risk of large cerebral infarction may increase when MCA stenosis exceeds 75% in grade.     

Renal artery lesions in patients with moyamoya disease: angiographic findings

BACKGROUND AND PURPOSE: Renal artery lesions in moyamoya disease have been described sporadically in several case reports. The purpose of this study is to evaluate the angiographic findings of renal artery lesions in moyamoya disease and to determine the prevalence of renal artery lesions in patients with moyamoya disease. METHODS: Eighty-six consecutive patients with idiopathic moyamoya disease were prospectively examined with both cerebral angiography and abdominal aortography. The findings of abdominal aortography were reviewed for the presence and appearance of renal artery lesions and compared with the clinical data and cerebral angiographic findings. RESULTS: Of 86 patients with idiopathic moyamoya disease, 7 patients (8%) were found to have renal artery lesions. Six patients (7%) had stenosis in the renal artery, and 1 patient (1%) had a small saccular aneurysm in the renal artery. Two patients (2%) with a marked renal artery stenosis presented with renovascular hypertension, which resulted in an intraventricular hemorrhage in 1 patient. Furthermore, the renal artery stenosis in the 2 patients with renovascular hypertension was successfully treated with percutaneous transluminal angioplasty. There was no significant correlation between the presence of renal artery lesions and cerebral angiographic findings. CONCLUSIONS: Seven (8%) of 86 patients with moyamoya disease showed renal artery lesions, including 6 stenoses (7%) and 1 aneurysm (1%). Renal artery lesions are a clinically relevant systemic manifestation in patients with moyamoya disease.     

Borderzone hemodynamics in cerebrovascular disease

To investigate the possible existence of chronic selective hemodynamic impairment in the arterial borderzone regions of the brain, we used positron emission tomography (PET) to measure regional mean vascular transit time (rt, equal to the ratio of regional cerebral blood volume to cerebral blood flow) and regional oxygen extraction fraction (rOEF) in 32 patients with either severe internal carotid artery stenosis or occlusion and 11 normal controls. Twenty-four of the patients had had TIAs or amaurosis fugax from 1 to 60 days before PET; all had normal brain CT. We used a stereotactic localization method to locate the anterior and posterior borderzone regions of the middle cerebral artery (MCA) territory. We then calculated ratios of each borderzone to the ipsilateral MCA territory for both rt and rOEF. There was no significant difference from control ratios in any patient subgroup including those with greater than or equal to 75% stenosis or occlusion, those with or without contralateral greater than or equal to 50% stenosis, or those with abnormal hemodynamics in the MCA territory. We therefore found no evidence for selective borderzone hemodynamic impairment in this group of patients with severe carotid artery disease.     

Multiple cerebrovascular occlusive disease associated with neurofibromatosis

Multiple cerebrovascular occlusive disease is rarely seen in patients with neurofibromatosis. Two cases of such lesions are presented and literatures dealing with the clinical and angiographical aspects of this occlusive disease are reviewed. Case 1; A 38-year-old normotensive man had sudden onset of vomiting, left hemiparesis and disturbance of consciousness, one day before the admission. He had family history of neurofibromatosis, and examination showed café au lait spots over the body. CT scans revealed a subcortical hematoma in the right temporal lobe. Angiogram revealed multiple occlusive lesions of the cerebral arteries, including occlusions of the right internal carotid artery (ICA) at the distal end, middle (MCA) and anterior (ACA) cerebral artery at the proximal portion, and stenosis of the left ICA and ACA. Abnormal vascular networks at the base of the brain were also seen bilaterally. Decompressive craniectomy, removal of the hematoma and bilateral ventricular drainage were performed. Postoperative course was excellent. Angiogram performed five and a half years later, during which time without any surgical procedures, demonstrated no apparent angiographic differences from the previous one. Case 2; A 29-year-old woman without family history of neurofibromatosis presented with sudden onset left hemiparesis. Café au lait spots were found over the body. A CT scan revealed small infarctions in the territory of the right MCA, and angiogram demonstrated multiple occlusive lesions of the cerebral arteries, including stenosis of the bilateral ICA, the left MCA, both ACAs at the proximal portion, and the right posterior cerebral artery, and occlusions of the right MCA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical and radiologic features of lacunar versus nonlacunar minor stroke

We determined the angiographic presence of extracerebral and intracerebral arterial disease in 122 patients with minor stroke within the carotid territory; we excluded patients with a recognized cardiac source of emboli. Based on clinical features and computed tomographic findings, patients were classified as having lacunar infarcts (n = 61), nonlacunar infarcts (n = 53), and infarcts of indeterminate type (n = 8). Severe carotid bifurcation disease (greater than or equal to 50% stenosis or occlusion) was significantly more common in nonlacunar than in lacunar infarcts, on both the ipsilateral (p less than 0.001) and the contralateral (p less than 0.01) sides; 79% of the patients with nonlacunar infarcts had severe carotid bifurcation and/or middle cerebral artery disease on the ipsilateral side compared with 3.3% of the patients with lacunar infarcts. Our data underscore the need for classification of patients by the underlying mechanisms in future studies of treatment of ischemic stroke.     

Cause of cerebral infarction in the carotid territory. Its relation to the size and the location of the infarct and to the underlying vascular lesion

Seventy-three patients with acute nonhemorrhagic stroke in the carotid territory were investigated for the cause of the stroke: middle cerebral artery (MCA) occlusion/stenosis or internal carotid artery (ICA) occlusion/stenosis; embolus from the heart and extra-cranial arteries or thrombosis. The study is prospective and consecutive comprising stroke patients below the age of 75 years, admitted in the acute state i.e. within 3 days after stroke onset. Excluded were patients with intracerebral hematoma, subarachnoid hemorrhage, vertebrobasilar stroke and patients in whom another severe disease was present. Cerebral angiography and CT-scan were performed in all patients within one and two days after admission. CT-scan was repeated 2 weeks and 6 months later. Forty percent had MCA occlusion, none had MCA stenosis, 12% had ICA occlusion, 14% had severe ICA stenosis (half of these were associated with MCA occlusion) and 41% were without significant MCA/ICA lesions. Twenty-seven percent had large infarcts with a diameter greater than 3 cm; 34% had medium-sized infarcts with a diameter between 3 and 1.5 cm; 21% had small infarcts with a diameter less than 1.5 cm; 18% had no identifiable infarct on CT-scan. MCA occlusion was responsible for 62% of the large or medium-sized infarcts. ICA occlusion or severe ICA stenosis were responsible for only 27% of the large or medium-sized infarcts. Only 11% of the patients with small or no infarct on CT-scan had significant MCA/ICA lesion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Brachiofacial pure motor stroke.

Pure motor stroke is the commonest lacunar syndrome, but it may be associated with nonlacunar mechanisms of infarction. Pure motor brachiofacial weakness has been considered as a partial syndrome depending on a lacunar mechanism. We studied the correlations between stroke type, topography of infarction and etiology in 22 patients with pure motor brachiofacial weakness who were consecutively admitted to our stroke unit during a 10-year period. Seventeen patients had a small deep infarct, 4 had a cortical infarct in the superficial MCA territory and 1 had no specific lesion. The part of the cardiovascular risk factors was about 36% for smoking, 13% for diabetes mellitus, 60% for dyslipidemia and 40% for heart disease. Hypertension was present in 75% of our cases. None of the patients had a large artery stenosis on Doppler ultrasonography. We concluded that brachiofacial pure motor stroke is not always correlated to lacunar infarcts and may be due to a cortical infarct. MRI should be performed when brain CT is normal because of the implications it may have in management and therapy.     

Carotid artery stenosis in ischemic stroke patients with nonvalvular atrial fibrillation.

PURPOSE: To study the prevalence, severity and clinical relevance of carotid atherosclerosis in ischemic stroke patients with nonvalvular atrial fibrillation (NVAF). MATERIAL AND METHODS: We reviewed carotid duplex sonography, computed tomography (CT) and clinical features in 103 consecutive ischemic stroke patients with NVAF. Both sonography and CT were performed within 3-7 days after stroke. There were 64 men and 39 women with a mean age at stroke onset of 69 years. RESULTS: High-grade (> or =50%) stenosis of the extracranial carotid artery was detected in 25 patients (24.3%), including 11 patients (10.6%) with internal carotid artery (ICA) occlusion. In 15 (66.7%) of the patients who had high-grade carotid stenosis, the lesion was ipsilateral to the infarct, including 8 ICA occlusions. Patients with high-grade stenosis smoked more cigarettes (p < 0.05) and had more peripheral vascular diseases (p < 0.05). Besides NVAF, all patients had more than one vascular risk factor. The clinical presentations (transient ischemic attacks, minor or major strokes) showed no significant difference between the groups of <50% and > or =50% stenosis. Clinical outcome was worse (dead and totally dependent in daily activities) in the group of high-grade stenosis (p < 0.05). Patients with high-grade carotid stenosis showed more cortical infarcts on cerebral CT (p < 0.01). Six out of 7 patients with a hemorrhagic transformation on the initial cerebral CT were in the low-grade carotid stenosis group, though this was statistically insignificant. CONCLUSIONS: Ischemic stroke with NVAF is not always cardiogenic. High-grade stenosis of the extracranial carotid artery is found in one fourth of ischemic stroke patients with NVAF and is related to more cortical infarction and worse clinical outcome. We speculate that ischemic stroke patients with NVAF who have high-grade carotid stenosis are less likely to develop hemorrhagic infarct. The pathogenesis of cerebral infarction and the therapeutic strategy in this clinical condition are complicated by the coexistence of carotid arterial lesions and cardiac disease.     

Cerebral infarction of the basal ganglia due to embolism from the heart

We studied 8 patients with cerebral infarction in the deep territory of the middle cerebral artery (MCA). All patients had a definite cardiac source of emboli and no known factors for thrombosis. Mixed sensory and motor deficit was found in all but one patient and CT scan showed larger lesions than usually reported in lacunar infarcts. Contrast enhancement was seen in all cases in which CT scan was performed in the second or third week. It is concluded that embolic infarcts in deep cerebral territory of MCA from a cardiac source are more frequent than previously reported. This diagnosis has to be considered when CT scan demonstrates a deep cerebral infarct.     

Long-term prognosis of cerebral infarction--influence of arterial stenotic lesion for survival (author's transl)

Cerebral four vessel angiography was performed in 85 patients with non-embolic cerebral infarction and followed for ten years. Of 45 patients with arterial stenosis of 25 per cent or more, 21 (46.7%) survived at 5 years and 12 (26.7%) at 10 years after onset of the stroke. In contrast, survivors of 45 patients with stenosis less than 25 per cent or with no stenotic lesion, were 35 (87.5%) at 5 years and 29 (72.5%) at 10 years after the onset. The survival rate of the former patients group was lower significantly than the expected survival rate in a general population. Arterial stenosis of 25 per cent or more suggested a trend of poor prognosis in patients with multiple stenosis, especially those of bilateral internal carotid arteries, and of better prognosis in patients with stenosis in vertebrobasilar system. Patients with stenosis of 50 per cent or more in sphenoidal portion of the middle cerebral artery seemed to have a poor prognosis than those in the internal carotid artery.     

症状性大脑中动脉狭窄斑块分布与中国卒中亚型相关性研究

目的观察症状性大脑中动脉(middle cerebral artery,MCA)狭窄患者狭窄段血管动脉粥样硬化斑块分布特点及其与中国缺血性卒中分型(Chinese Ischemic Stroke Subclassification,CISS)中缺血性卒中发病机制的关系。方法采用前瞻性研究方法,连续收集大脑中动脉狭窄所致初发缺血性卒中患者,依据高分辨率磁共振成像(high-resolution magnetic resonance imaging,HRMRI)所显示的动脉粥样硬化斑块分布的位置将患者分为上壁组、下壁组、腹侧组、背侧组,比较不同象限斑块分布引起缺血性卒中的机制是否存在差异。结果 HRMRI能够清楚地显示大脑中动脉管壁结构,入组27例患者中腹侧斑块10(37.03%)例,背侧斑块3(11.11%)例,上壁斑块7(25.93%)例,下壁斑块7(25.93%)例。男性患者动脉粥样硬化斑块常见于腹侧,女性患者动脉粥样硬化斑块常见于背侧。上壁组动脉粥样硬化斑块堵塞穿支动脉病变6例(85.7%),下壁组穿支病变1例(14.3%),腹侧组穿支病变0例(0%),背侧组穿支病变3例(100%),差异有显著性(P0.001)。结论本组症状性大脑中动脉狭窄患者中动脉粥样硬化斑块多发生于动脉腹侧,与穿支动脉开口相对;上壁和背侧斑块易堵塞穿支动脉开口而引起缺血性事件。