急性血栓性大脑中动脉栓塞脑缺血模型的建立

目的评价急性血栓性大鼠大脑中动脉栓塞(MCAO)脑缺血造模的可行性,旨在提高模型的可重复性和可控制性。方法健康雄性成年SD大鼠60只,体重300～450g,随机分为3组:大栓子组(栓子长1.2～1.5mm,15只)、中等栓子组(0.8～1.0mm,30只)和小栓子组(0.5～0.6mm,15只)。取同系大鼠的股动脉血0.6ml与0.15ml凝血酶溶液混匀后,注入微导管内制备成线样血栓。将切好的栓子经大鼠左侧颈内动脉注入,建立MCAO模型。使用GESigna1.5T超导成像仪,3英寸环形表面线圈行大鼠脑MRI检查,并将检查结果与病理结果对照。结果小栓子组15只,9只发现脑梗死灶(60%),中等栓子组和大栓子组所有大鼠均出现脑梗死灶,小栓子组与另2组比较差异有统计学意义(P<0.05)。中等栓子组脑梗死灶均位于同侧大脑半球,局限于左侧顶叶皮质、皮层下及基底节的占93.3%(28/30)。小栓子组9只,在24h或死亡时的平均脑梗死体积占同侧大脑半球的(14.41±8.72)%,中等栓子组30只占(48.29±18.57)%,大栓子组15只占(73.68±18.29)%。3组之间脑梗死体积比较差异有统计学意义(F=33.171,P<0.01)。小栓子组9只,平均生存时间(301.1±23.02)h;中等栓子组30只,平均生存时间(277.43±20.27)h;大栓子组15只,平均生存时间(59.93±25.03)h。大栓子组与另2组之间生存时间比较差异有统计学意义(F=24.676,P<0.01),而中等栓子组的生存时间与小栓子组比较差异无统计学意义(P>0.05)。中等栓子组脑梗死区相对脑血流容量(rCBV)在3～18h内比较差异无统计学意义(F=1.578,P>0.05)。结论经过改良后,中等栓子建立的大鼠MCAO模型脑梗死体积适中、存活率高、脑梗死部位恒定而rCBV持续降低,具有良好的可重复性和可控性。     

Asymptomatic middle cerebral artery stenosis diagnosed by magnetic resonance angiography

We reviewed 1440 MRA studies to identify patients with middle cerebral artery stenosis (MCAS). We identified 99 cases, and after reviewing the clinical records, classified 28 as asymptomatic MCAS (AMCAS), a prevalence of 2%. Suspected stroke was the most frequent indication for MRA. Follow-up was available for 21, mean 46.7 months (range 2.4–75.6 months). One stroke occurred in the AMCAS territory (5%), other strokes in five patients (24%). There were five deaths in patients with MCAS; age >69 ( P =0.045) was the only associated risk factor. This study suggests that patients in whom MRA is performed and shows AMCAS may be at increased risk of strokes in any vascular distribution or of death.Presented in part as an abstract at the 27 ^th International Stroke Meeting, San Antonio, Texas, February 2002 and the 54 ^th American Academy of Neurology Meeting, Denver, Colorado, April, 2002     

The prominent hypointense vessel sign on susceptibility-weighted imaging (SWI) as a potential imaging biomarker for poor clinical outcome in acute ischemic stroke (AIS)

Susceptibility-weighted imaging (SWI) is a relatively new magnetic resonance imaging (MRI) technique used in the workup and diagnosis of brain pathologies. In the context of acute ischemic stroke (AIS), it is increasingly becoming useful in the diagnosis, treatment, and further management of these patients. An elderly man with metabolic syndrome presented to us with an acute onset of right sided body weakness and aphasia. Urgent imaging via MRI noted a left middle cerebral artery (MCA) occlusion. Diffusion-weighted imaging (DWI)/fluid attenuated inversion recovery (FLAIR) mismatch was noted with an acute infarct involving the left MCA territory; hence, treatment with intravenous (IV) thrombolysis was administered. On SWI, the prominent hypointense vessel sign was noted. Recanalization of the occluded left MCA was seen on diagnostic cerebral angiography post IV thrombolysis, however, the patient was noted to have early neurological deterioration (END) and poor early stage clinical outcome, despite repeat MRI showing recanalization of the left MCA occlusion and reversal of the prominent hypointense vessel sign on SWI. Presence of the prominent hypointense vessel sign on SWI in AIS patients is associated with poor clinical outcome, unsuccessful recanalization rates, END, poor early stage clinical outcome, and infarct core progression. Some studies have shown an association between this imaging sign and poor collateral circulation status. Therefore, this imaging sign could potentially prove to be a useful imaging biomarker. However, more studies are needed to validate this theory.     

High resolution MR imaging in patients with symptomatic middle cerebral artery stenosis

Purpose

High resolution magnetic resonance imaging (HRMRI) has been used as an imaging modality to depict the intracranial artery wall. The aim of this study was to compare images of the vessel wall between symptomatic and asymptomatic atherosclerotic plaques of the middle cerebral artery (MCA) using HRMRI.

Materials and methods

From September 2009 to August 2010 we prospectively screened consecutive patients for MCA stenosis using time-of-flight (TOF) MR angiography. We studied 14 patients with symptomatic MCA stenosis and 16 patients with asymptomatic MCA stenosis. The HRMRI protocol included three different scans: T1-, T2-, and proton density (PD)-weighted black blood MRI. The cross-sectional images of the MCA wall on HRMRI were compared between the two groups based on the degree of stenosis, remodeling ratio, outward or inward remodeling, plaque signal intensity, plaque surface irregularity, and presence of an intact inner wall.

Results

The degree of MCA stenosis and the ratio of plaque thickening to patent lumen in the symptomatic group were significantly higher than in the asymptomatic group. Outward remodeling of the stenotic area in symptomatic group was significantly higher than that seen in the asymptomatic group, and the reverse was true for inward remodeling of the stenotic area (it was significantly higher in the asymptomatic group compared to the symptomatic group). T2- and PD-weighted high signal foci, eccentric wall thickening, and plaque volume in the stenotic area were all similar between the two groups.

Conclusions

HRMRI has the potential to distinguish between atherosclerotic plaques in symptomatic and asymptomatic MCA stenoses.     

Mechanical thrombectomy in acute stroke for superior limb of the fenestration of the middle cerebral artery

Fenestration of the middle cerebral artery (MCA) is a rare anatomic variant, and lenticulostriate arteries (LSAs) often arise from the superior limb of the fenestrated segment. A case of acute occlusion of the superior limb of a fenestrated MCA that successfully underwent mechanical thrombectomy is presented. Digital subtraction angiography performed for a 73-year-old man with acute left hemiparesis showed poor visualization of the upper half of the right M1 segment with maintenance of antegrade peripheral circulation of the MCA territory, and mechanical thrombectomy was successfully performed using a stent retriever with intravenous thrombolysis. After restoration of the MCA, the vascular variant of a fenestrated MCA was found. Clinicians must consider the possibility of acute occlusion of a fenestrated MCA before endovascular thrombectomy. Restoration of acute occlusion of the upper limb of a fenestrated MCA can avoid LSA territory infarction.     

急性单侧大脑中动脉供血区局灶性梗死患者胼胝体各向异性的MRI初步研究

目的:利用MR DWI技术探讨单侧大脑中动脉供血区急性脑梗死时胼胝体各部分各向异性可能存在的变化。方法:连续选取病灶位于单侧大脑中动脉供血区的急性脑梗死患者66例(分为4组)及同期行MRI检查且年龄、性别与病变组匹配的66例40岁以上健康成人作为对照组。应用SSEPI序列行正中矢状面DTI扫描,在FA图上分别测量胼胝体膝部、体部前1/3处、体部中部、体部后1/3处及压部的FA值并进行统计学分析。结果:胼胝体体部前1/3处、体部中部及体部后1/3处的FA值均为正常组大于梗死组,胼胝体体部前1/3处及体部后1/3处的FA值正常组(分别为0.698±0.054和0.769±0.049)与梗死组(分别为0.665±0.049和0.653±0.078)之间差异存在统计学意义(t值为2.697和7.381,P<0.05)。胼胝体膝部及压部FA值均为梗死组(分别为0.780±0.082和0.772±0.049)大于正常组(分别为0.723±0.061和0.748±0.049),且两组之间差异有统计学意义(t值为-3.28和-2.08,P<0.05)。结论:单侧大脑中动脉供血区发生急性梗死时,连接双侧脑半球相应部位的胼胝体体部各向异性值减低,非承担这些脑叶间相互连接功能的膝部及压部各向异性值增高。     

MELAS presenting as migraine complicated by stroke: case report

A case of MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) which presented as migraine complicated by stroke is reported. Strokes associated with migraine have often been reported, but the mechanism remains unclear and may include a variety of pathologies. MELAS also presents with migrainous headache, vomiting, and stroke-like symptoms. Magnetic resonance imaging demonstrates characteristic findings. MELAS should be considered in the differential diagnosis of infarct-like lesions with migrainous headaches in young adults, especially if the symptoms fluctuate and are accompanied by a homonymous hemianopia. Received: 23 September 1996 Accepted: 19 February 1997     

Schizencephaly with occlusion or absence of middle cerebral artery

In a study of 160 infants with prenatal and/or perinatal risk factors for brain damage, we observed three cases of schizencephaly. All cases were unilateral, and the clefts had open lips. In two cases, magnetic resonance angiography showed occlusion or absence of the middle cerebral artery (MCA) on the affected side. Two of the patients, including one with absent flow in the MCA of the affected side, had ipsilateral cerebellar atrophy.     

Impact of diffusion-weighted MRI-measured initial cerebral infarction volume on clinical outcome in acute stroke patients with middle cerebral artery occlusion treated by thrombolysis

Introduction: Magnetic resonance imaging (MRI) may help identify acute stroke patients with a higher potential benefit from thrombolytic therapy. The aim of our study was to assess the correlation between initial cerebral infarct (CI) volume (quantified on diffusion-weighted MRI) and the resulting clinical outcome in acute stroke patients with middle cerebral artery (MCA) (M_1–2 segment) occlusion detected on MRI angiography treated by intravenous/intraarterial thrombolysis.Methods: Initial infarct volume (V_DWI-I ) was retrospectively compared with neurological deficit evaluated using the NIH stroke scale on admission and 24 h later, and with the 90-day clinical outcome assessed using the modified Rankin scale in a series of 25 consecutive CI patients. The relationship between infarct volume and neurological deficit severity was assessed and, following the establishment of the maximum V_DWI-I still associated with a good clinical outcome, the patients were divided into two groups (V_DWI-I ≤70 ml and >70 ml).Results: V_DWI-I ranged from 0.7 to 321 ml. The 24-h clinical outcome improved significantly (P=0.0001) in 87% of patients with a V_DWI-I ≤70 ml (group 1) and deteriorated significantly (P=0.0018) in all patients with a V_DWI-I >70 ml (group 2). The 90-day mortality was 0% in group 1 and 71.5% in group 2. The 90-day clinical outcome was significantly better in group 1 than in group 2 (P=0.026).Conclusion: Clinical outcome could be predicted from initial infarct volume quantified by MRI-DWI in acute CI patients with MCA occlusion treated by intravenous/intraarterial thrombolysis. Patients with a V_DWI-I ≤70 ml had a significantly better outcome.This paper was presented in part as a lecture at the 9th Congress of the European Federation of Neurological Societies Athens, Greece, 17–20 September 2005.     

Proton magnetic resonance spectroscopy in patients with symptomatic unilateral internal carotid artery / middle cerebral artery stenosis or occlusion

Purpose:

To explore the value of proton magnetic resonance spectroscopy imaging (¹H‐MRSI) in patients with stenosis or occlusion of the internal carotid artery (ICA) / middle cerebral artery (MCA).

Materials and Methods:

Fifty noninfarcted patients with stenosis or occlusion of unilateral ICA/MCA were included in our study. In the meantime, 25 patients with cerebral infarction and 25 healthy control subjects were enrolled. All patients and healthy control subjects underwent ¹H‐MRSI. Cerebral metabolic changes were studied in the noninfarcted patients and compared with the infarcted patients as well as healthy control subjects.

Results:

In 50 noninfarcted patients N‐acetylaspartate (NAA) decreased and choline increased in the ischemic hemisphere compared with the contralateral side and control subjects. Lactate peaks were observed in 12 patients. The metabolic changes were relatively slight but were associated with metabolic disruption in infarcted patients. There were relationships between metabolic abnormalities and neurological status of the noninfarcted patients.

Conclusion:

¹H‐MRSI can demonstrate abnormal metabolic changes in cerebral tissues with no infarction, while with ICA/MCA may show stenosis or occlusion at an early stage, which may help guide treatment decisions and preoperative evaluation. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Recurrent stroke syndrome without abnormality on magnetic resonance imaging caused by stenosis of middle cerebral artery: A case report

Middle cerebral artery stenosis is the leading and the most frequent cause of stroke due to intracranial stenosis in Asia. Magnetic resonance imaging (MRI) is more sensitive than computed tomography of the head for detecting acute brain ischemia. We are reporting a case of a 28-year-old female with recurrent left hemiparesis. After the last attack, an improvement in motor function was seen in less than 24 hours. Though the restoration of motor functions is not complete yet, an MRI scan that was done two weeks later appeared normal. Ischemic stroke in middle cerebral artery stenosis is associated with hemodynamic stroke due to hypoperfusion or lack of blood flow to brain tissue. Recurrent strokes can be prevented by better medical management in patients through regulation and management of risk factors.     

A giant fusiform middle cerebral artery treated by low-flow superficial temporal artery bypass: A case report

A giant fusiform aneurysm of the middle cerebral artery is a disease that causes many difficulties for endovascular intervention as well as surgery. No 1 solution is optimal for all cases, however for post-bifurcation aneurysms, trapping the aneurysms with a reanastomosis reimplantation, an in situ side to side bypass is feasible and has good results. We reported a 28-year-old male patient, admitted to the hospital because of severe headache, Glasgow Coma Scale 13 points, left hemiplegia, was diagnosed with subarachnoid hemorrhage due to rupture of a giant fusiform aneurysm of the middle cerebral artery in the M2 segment, Hunt and Hess grade 4. The patient underwent microsurgery with clipping aneurysm combined with a low-flow technique connecting the superficial temporal artery to the middle cerebral artery. Our findings suggest that surgery to connect the superficial temporal artery to the M2 segment and at the same time obstructing the parent artery occlusion of selected giant MCA aneurysm is an option to consider     

猴可复性大脑中动脉闭塞模型脑缺血半暗带的血氧水平依赖效应

目的 探讨血氧水平依赖(BOLD)MRI对确定猴脑缺血半暗带(IP)的价值.方法 成年恒河猴6只,应用微导管法制作猴可复性大脑中动脉闭塞(MCAO)模型.MCAO后0 h、再灌注后1、3、 6、 12、24及48 h分别进行DWI、PWI、T_2 WI、定量T_2和T_2~* 扫描,根据T_2和T_2~* 图计算可逆性横向弛豫率(R_2'),用来表示BOLD效应(R_2' BOLD).计算动脉闭塞期DWI(0 h DWI)、再灌注48 hT_2WI(48 h T_2WI)及脑组织大体切片2,3,5-氯化三苯基四氮唑(TTC)染色病灶体积百分比(病灶体积/双侧大脑半球体积).将缺血组织划分为3个区域:梗死核心(0 h DWI、48 h T_2WI均为高信号区)、IP(0 h DWI高信号,48 h T_2WI等信号区)及低灌注区(0 h平均通过时间延长但0 h DWI、48 hT_2WI均为等信号区),分别测最3个区域R_2'的相对值(患侧/健侧半球镜影区比值,rR_2').病灶体积比比较采用配对t检验和相关分析,3个区域rR_2'比较采用单因素方差分析.结果 6只猴中4只造模成功.48 h _T2WI病灶体积比(8.16±0.55)%较0 h DWI的(11.37±1.41)%明显缩小(t=6.472,P<0.05);TTC染色病灶体积比(8.15±0.62)%与48 h T_2WI的(8.16±0.55)%差异无统计学意义(t=0.150,P>0.05),两者呈明显正相关(r=0.98,P<0.05).梗死核心、IP、低灌注区rR_2'在各时间点差异均有统计学意义,梗死核心低于IP,IP低于低灌注区(P<0.05),三者rR_2'值:0 h时分别为1.129±0.108、1.329±0.081、1.584±0.103(F=36.19,P<0.05).1 h分别为0.668±0.082、1.237±0.072、1.435±0.066(F=134.09,P<0.05).3 h分别为0.536±0.075、1.453±0.081、1.770±0.141(F=256.30,P<0.05).6 h分别为0.259±0.050、2.435±0.131、2.957±0.177(F=803.25,P<0.05).12 h分别为0.385±0.054、2.447±0.148、3.254±0.184(F=743.74,P<0.05).24 h分别为0.083±0.026、1.968±0.127、3.101±0.144(F=1236.26,P<0.05).48 h分别为0.246±0.058、3.694±0.218、4.297±0.322(F=557.02,P<0.05).随再灌注时间延长,IP和低灌注区的rR_2'呈逐渐升高趋势,表现为负性BOLD效应;梗死核心呈逐渐降低趋势,表现为正性BOLD效应.结论 R_2' BOLD可以根据缺血脑组织氧代谢状态的不同来区分IP和梗死核心.     

高分辨力MR成像检查大脑中动脉粥样硬化斑块的研究进展

颅内动脉粥样硬化在亚洲是缺血性卒中的主要病因,其在我国的脑卒中和短暂性脑缺血发作中也有较高发生率。高分辨力MR成像作为目前唯一可以在体进行的血管壁成像的无创技术,临床应用越来越广泛,尤其是对大脑中动脉的研究。高分辨力MR成像能评估动脉管腔的狭窄程度、斑块分布、斑块信号特点、管壁重构方式等,为临床治疗提供更多的有用信息。现就近年来高分辨力MR成像检查颅内大脑中动脉粥样硬化斑块的研究进展进行综述。     

单侧大脑中动脉狭窄程度与磁共振血流灌注相关性研究

目的:探讨大脑中动脉(MCA)狭窄程度与脑磁共振灌注加权成像(PWI)的相关性。方法:30例短暂性脑缺血发作(TIA)患者行高分辨力MRI检查并判断单侧MCA狭窄程度,同时行磁共振PWI检查,并对MCA不同狭窄状态下得出的患侧和镜像侧灌注参数,包括相对脑血容量(rCBV)、相对脑血流量(rBCF)、相对平均通过时间(rMTT)、相对达峰时间(rTTP)进行定量分析。结果:30例患者中,高分辨力MRI均可显示不同程度MCA狭窄,灌注均出现异常,患侧灌注参数rCBV、rCBF、rMTT、rTTP与镜像侧比较,差异均有统计学意义(P<0.05)。MCA狭窄率与rMTT延长百分率之间呈正相关性(r=0.45,P<0.05)。结论:高分辨力MRI对MCA狭窄程度的评估与PWI灌注参数之间存在正相关性,MCA狭窄程度与PWI相结合对于评价脑组织供血有一定的指导意义。     

A case of bilateral dense middle cerebral arteries with CT angiographic confirmation of vascular occlusion

Hyperattenuating middle cerebral arteries on CT in acute stroke should generally not be associated with presence of intraluminal clot when bilaterally seen. We report a case of a woman who underwent emergency CT 60 min after sudden onset of coma. Bilateral dense middle cerebral arteries without parenchymal hypoattenuating areas or indirect signs of cerebral edema were present. CT angiography confirmed occlusion of the right middle cerebral artery and left internal carotid artery and middle cerebral artery.     

症状性缺血性脑卒中颈动脉斑块成分的 高分辨MRI分析

目的应用高分辨MRI(HRMRI)探讨颈动脉斑块不同成分在症状性缺血性脑卒中病人中的危险性。方法选取2016年1月—2017年6月于我院行超声检查发现存在颈动脉斑块的病人50例,其中女21例,男29例,年龄43~77岁,平均(61.62±7.96)岁。依据病人近3个月来是否发生过与患侧颈动脉相关的缺血性脑卒中临床症状分为有症状组(22例,存在斑块血管40支)及无症状组(28例,50支),所有病人行3.0 T HRMRI以评估颈动脉血管及斑块内成分。采用χ~2检验或t检验对2组病人的临床资料、斑块成分及血管管腔狭窄程度进行比较,采用logistic回归分析缺血性脑卒中病人症状的独立危险因素。结果检出存在斑块纤维帽破溃(FCR)的血管,症状组15支,检出率为37.5%,无症状组8支,检出率为16.0%,症状组FCR的检出率高于无症状组(P0.05)。检出斑块内出血(IPH)的血管,症状组21支,检出率为52.5%,无症状组15支,检出率为30.0%,症状组IPH的检出率高于无症状组(P0.05)。检出存在斑块钙化(CA)的血管,症状组15支,检出率为37.5%,无症状组13支,检出率为26.0%,2组间检出率差异无统计学意义(P0.05)。症状组管腔狭窄程度为57.64%±13.36%,无症状组为53.86%±11.19%,2组间管腔狭窄程度差异无统计学意义(t=1.460,P=0.148)。FCR在症状性缺血性脑卒中危险性最高(OR=3.012),IPH危险性次之(OR=2.478)。结论 HRMRI可以分析斑块内成分,而这些成分是缺血性脑卒中临床症状发生的危险因素,是斑块易损性的表现。     

Posterior reversible encephalopathy syndrome mimicking subacute ischemic stroke: a case report

Posterior reversible encephalopathy syndrome, an acute onset neurological syndrome, is among the conditions that must be differentiated from stroke. Herein, we report a rare case of posterior reversible encephalopathy syndrome mimicking subacute ischemic stroke. A 68-year-old man was transferred by ambulance to our hospital because of visual disturbance. He showed left homonymous hemianopsia. Magnetic resonance imaging (diffusion-weighted imaging and fluid-attenuated inversion recovery imaging) revealed high signal intensity in the right occipital lobe. We suspected subacute cerebral infarction. After admission, he developed cortical blindness and increased blood pressure. Fluid-attenuated inversion recovery imaging revealed high signal intensity and elevated apparent diffusion coefficient values in the bilateral occipital lobes. We diagnosed the patient with posterior reversible encephalopathy syndrome. Antihypertensive treatment improved his clinical symptoms. Careful imaging assessment, including of changes over time, is important for diagnosing posterior reversible encephalopathy syndrome.     

人工智能在急性缺血性脑卒中成像中的应用进展

人工智能(AI)技术可采用多种算法模拟人类认知和信息处理过程,与CT和MRI相结合可用于急性缺血性脑卒中成像,包括梗死灶的检测、影像分割、头颈大血管闭塞的检测和病人预后预测等。采用AI技术分析或构建模型有助于临床医师对脑卒中病人的尽早诊疗、及时干预和随访评估。概述AI的概念,并就其在急性缺血性脑卒中病人CT平扫、CT血管成像(CTA)、CT灌注成像(CTP)、MRI中的应用进展进行综述。     

Intraarterial reteplase and intravenous abciximab for treatment of acute ischemic stroke

We performed a preliminary feasibility and safety study using intravenous (IV) administration of a platelet glycoprotein IIb/IIIa inhibitor (abciximab) in conjunction with intraarterial (IA) administration of a thrombolytic agent (reteplase) in a primate model of intracranial thrombosis. We introduced thrombus through superselective catheterization of the intracranial segment of the internal carotid artery in 16 primates. The animals were randomly assigned to receive IA reteplase and IV abciximab ( n =4), IA reteplase and IV placebo ( n =4), IA placebo and IV abciximab ( n =4) or IA and IV placebo ( n =4). Recanalization was assessed by serial angiography during the 6-h period after initiation of treatment. Postmortem magnetic resonance (MR) imaging was performed to determine the presence of cerebral infarction or intracranial hemorrhage. Partial or complete recanalization at 6 h after initiation of treatment (decrease of two or more points in pre-treatment angiographic occlusion grade) was observed in two animals treated with IA reteplase and IV abciximab, three animals treated with IA reteplase alone and one animal treated with IV abciximab alone. No improvement in perfusion was observed in animals that received IV and IA placebo. Cerebral infarction was demonstrated on postmortem MR imaging in three animals that received IA and IV placebo and in one animal each from the groups that received IA reteplase and IV abciximab or IV abciximab alone. One animal that received IV abciximab alone had a small intracerebral hemorrhage on MR imaging. IA reteplase with or without abciximab appeared to be the most effective regimen for achieving recanalization in our model of intracranial thrombosis. Further studies are required in experimental models to determine the optimal dose, method of administration and efficacy of these medications in acute ischemic stroke.