单侧颈内动脉狭窄或闭塞后侧支循环与脑缺血关系的研究

目的 探讨单侧颈内动脉狭窄或闭塞后侧支循环与脑缺血的关系.方法 对比分析68例单侧颈内动脉狭窄或闭塞患者(实验组)及20例脑血管DSA检查正常者(对照组)的临床资料及数字减影血管造影(DSA)表现.结果 (1)实验组68例中,狭窄或闭塞发生于颈内动脉41例、大脑中动脉17例、大脑前动脉A1段4例、大脑前动脉A1段以远6例.发现侧支循环开放代偿共109例次,其中前交通动脉32例次、后交通动脉22例次、后软脑膜吻合27例次、前软脑膜吻合19例次、眼动脉4例次、穿支动脉2例次、其他3例次.重度狭窄组与闭塞组侧支循环开放率较高,分别为72.7％、86.7％,与正常对照组差异有显著性(x2=14.029、25.301,P均＜0.001);轻、中度狭窄组侧支循环开放率较低,分别为为16.7％、20.0％,与正常对照组差异无显著性(P=0.676、P=0.551).(2)初级侧支循环开放的比例:症状组小于无症状组,差异有显著性(P=0.042);次级侧支循环开放的比例:症状组大于无症状组,差异有显著性(P =0.022).前交通动脉开放的比例:症状组小于无症状组,差异有显著性(P=0.038);后交通动脉开放的比例:症状组与无症状组无显著性差异(P=0.382).(3)Willis前环变异:症状组最高,其次为正常对照组,而无症状组变异率最低,三组间差异有显著性(P =0.032);Willis后环变异比例:三组间差异无显著性(P=0.110).(4)颈内动脉闭塞的26例,侧支血流评分:梗死组得分最低为(2.4286±0.17271)分,其次为TIA组(3.2500 ±0.2500)分,最高的为无症状组(3.7500±0.16366)分,三组间差异有显著性(F=13.903,P＜0.001).结论 DSA对侧支循环状况的分析、评估具有非常重要的价值,能为颈内动脉狭窄或闭塞的诊断、治疗、预后提供较全面的评价.     

颈内动脉狭窄时侧支循环与脑梗死关系的研究

目的 探讨颈内动脉狭窄时各侧支循环途径出现的概率及与脑梗死的关系.资料与方法 将脑血管造影(DSA)发现颈内动脉狭窄>70%的43例患者作为研究对象,并将其中23例脑梗塞患者作为症状组;20例无脑梗死患者作为无症状组.观察侧支循环的组成、Willis环是否变异及其组成血管的管径,分析侧支循环与脑梗死的关系.结果 Willis环代偿是主要的侧支循环,症状组前、后环的变异率大于无症状组,症状组前交通动脉的管径为(1.2540±0.1438)mm,小于无症状组(1.4306±0.2199)mm(P=0.006).结论 颈内动脉狭窄患者是否出现缺血性症状与Willis环的代偿能力相关,Willis环的代偿潜能与Willis环是否存在变异及前交通动脉、后交通动脉的管径有关.     

颈内动脉狭窄或闭塞后侧支循环与脑缺血的关系研究

目的 探讨颈内动脉狭窄或闭塞后侧支循环与脑缺血的关系。资料与方法 颈内动脉狭窄或闭塞患者40例．分析MRA、MRI表现及临床资料。结果 40例患者59侧有颈内动脉分叉以上狭窄或闭塞，MRI上大面积脑梗死10例．腔隙性梗死15例．介于二者之间者4例．严重半球脑萎缩3例，轻度脑萎缩4例．无异常表现者4例。MRA上大面积梗死及严重脑萎缩者侧支循环很差或缺乏。腔隙性梗死、轻度脑萎缩及表现正常者均有较丰富的侧支循环。结论 颈内动脉狭窄或闭塞后脑缺血程度与侧支循环有密切关系。侧支循环差或缺乏，会引起大面积梗死．侧支循环丰富，不出现梗死或只引起小的梗死。     

利用灌注MRI技术评价颈内动脉狭窄或闭塞的血流动力学状态

目的 利用灌注磁共振成像(PWI)技术分析颈内动脉狭窄或闭塞时的血流动力学特点。资料与方法 搜集46例单侧颈内动脉狭窄或闭塞患者的资料，借助PWI对其血流动力学特点进行评价。结果 所有患者局部脑血流量没有显著性降低，但大脑中动脉分布区灌注明显延迟，在重度狭窄及闭塞时，分水岭区的灌注也出现障碍；不同的侧支循环代偿仅对大脑中动脉分布区的灌注有所影响，其中前交通动脉作用较为明显。结论 单侧颈内动脉狭窄时，PWI可以准确评价患者的血流动力学状况，而此时的血流动力学障碍与狭窄程度及侧支循环代偿均有明显的关系。     

颈内动脉闭塞后脑梗死分布与侧支循环代偿的相关性研究

目的探讨颈内动脉闭塞时脑梗死的发生机制及侧支循环对不同部位脑梗死的影响。方法 2009年1月至2010年9月收治急性脑梗死患者45例,均行磁共振弥散成像(DWI)和数字减影血管造影(DSA)检查,证实一侧颈内动脉闭塞并引起同侧新发梗死。记录梗死分布部位及侧支循环开放情况,分析颈内动脉闭塞引起同侧脑梗死的分布特征与前、后交通动脉开放的相关性。结果 45例中,颈内动脉闭塞后梗死分布依次为皮层微小梗死38例(84.4%),内分水岭梗死22例(48.9%),流域性梗死21例(46.7%),后分水岭梗死10例(22.2%),前分水岭梗死6例(13.3%),穿支动脉供血区梗死10例(22.2%)。其中皮层微小梗死合并分水岭梗死23例(60.5%)。前交通动脉开放时无流域性梗死(0%,P=0.013);12例无一级侧支开放者发生流域性梗死11例(91.7%,P=0.003)。结论动脉到动脉栓塞机制与低灌注/栓子清除障碍机制共同参与了颈内动脉闭塞引起的脑梗死。前交通动脉开放可以降低流域性梗死发生率。     

Visualizing cerebral arterial collaterals:MRI using vessel-encoded arterial spin labeling perfusion imaging compared with DSA

目的:使用血管编码动脉自旋标记(VE-ASL)技术在评价颈动脉狭窄患者通过Willis环与软脑膜动脉形成的侧支循环中的价值.方法:对经超声检查诊断为单侧颈内动脉中度以上狭窄或大脑中动脉血流速度明显增加的10例患者,行VE-ASL MRI检查,测量连续7个脑部层面(层厚8mm,间隔2mm),使用红绿蓝三种伪彩色分别标记来源于右侧颈内动脉、左侧颈内动脉和后循环的血流.所有患者在MRI检查前后1周内行DSA检查.将狭窄侧大脑半球侧支循环情况分为4种类型.Ⅰ型:仅来源于对侧颈内动脉;Ⅱ型:仅来源于后循环;Ⅲ型:既来源于对侧颈内动脉,也来源于后循环;Ⅳ型:既无对侧颈内动脉供血,也无后循环的侧支供血.记录患者侧支血流中软脑膜动脉侧支的数目.计算卡帕值比较两种测量方法之间的一致性.结果:比较VE-ASL和DSA方法,DSA对侧支循环的分型结果Ⅰ型1例,Ⅱ型2例,Ⅲ型5例,Ⅳ型2例;VE-ASL分型结果为Ⅰ型1例,Ⅱ型3例,Ⅲ型4例,Ⅳ型2例.两种检查方法的诊断一致性非常好(Kappa=0.8551,Z=4.421,P＜0.0001)10例中观察到6例8处软脑膜侧支血流.结论:对颈内动脉狭窄患者,VE-ASL可以无创地评价脑动脉通过Willis环及软脑膜动脉形成的侧支循环.     

烟雾病数字减影血管造影的诊断价值

目的评价数字减影血管造影(DSA)对烟雾病的诊断价值。材料与方法对13例烟雾病患者行DSA检查及回顾性分析。结果13例烟雾病DSA表现为不同程度颈内动脉分叉处血管狭窄或闭塞,侧支循环形成呈烟雾状。结论DSA可清晰地显示烟雾病血管狭窄程度或闭塞的部位及侧支循环情况,为临床治疗提供直接的影像学资料。     

经颅多普勒对颈内动脉颅外段重度狭窄或闭塞的颅内血流动力学分析

目的研究经颅多普勒超声（TCD）对颈内动脉颅外段重度狭窄或闭塞后颅内血流动力学参数的变化，探讨其临床应用价值。方法对32例经TCD诊断为颈内动脉颅外段重度狭窄或闭塞患者，分析其双侧大脑中动脉（MCA）、大脑前动脉（ACA）、大脑后动脉（PCA）的收缩期峰值流速（PSV）及血管搏动指数（P1），判断侧支循环开放类型，并以30例正常体检人群作为对照组，所得结果进行统计学分析。结果一侧颈内动脉颅外段重度狭窄或闭塞后，其颅内血流参数与正常对照组比较，存在明显的不对称性，经统计学t检验，差异有显著意义。TCD检测侧支循环开放例数与DSA比较，经统计学X^2检验，二者无差异（P〉0．05）。结论TCD能准确地检测到颈内动脉颅外段重度狭窄或闭塞后颅内血流动力学的变化，为临床选择治疗方法及判断预后提供有价值的信息。     

PWI联合MRA评价侧支循环在后循环远端缺血中的代偿作用

目的 探讨磁共振灌注加权成像(PWI)联合磁共振血管造影(MRA)评价侧支循环在后循环远端缺血中的代偿作用.方法 搜集32例伴有椎基底动脉重度狭窄的后循环缺血患者(病例组),分析PWI和MRA检查资料,并与30名健康志愿者(对照组)比较,观察后循环血管狭窄程度,侧支血管的显示,局部脑血流量(rCBF)、局部脑血容量(rCBV)、平均通过时间(rMTT)指标.结果 病例组中后交通动脉开放22例;软脑膜动脉显示11例;微小动脉团显示12例.病例组ROL/额叶白质比值相对于对照组rCBF、rCBV值均下降,MTT值延长,两组参数比较P值均＜0.05,有统计学差异.病例组中有后交通开放的患者与未开放的患者比较,rCBF升高,MTT缩短,P值均＜0.05;而rCBV两组间比较,P值=0.36(＞0.05),无统计学差异.结论 PWI联合MRA可以客观地评价后交通动脉在后循环远端缺血中的代偿作用,为临床治疗及判断预后提供帮助.     

用~(99m)Tc-ECD-RVR法对脑主干动脉病变患者脑循环潜能的评价

作者采用Diamox(乙酰唑胺)负荷脑血流SPECT法对脑主干动脉病变患者脑循环潜能进行评价,研究对象是MRI检查怀疑颈动脉或大脑中动脉病变、通过DSA以及多普勒检查确认其狭窄程度达70％以上的63例患者。并以24例无狭窄者为对照组来分析脑循环的潜能。63例中两侧颈内动脉狭窄或闭塞者18例,单侧颈内动脉闭塞14例,单侧颈内动脉狭窄18例,大脑中动脉狭窄或闭塞13例。做     

MRA与CDS对头颈部动脉狭窄或闭塞的对照研究

目的：探讨ＴＯＦ法ＭＲ血管成像（ＭＲＡ）所箜呈闭塞与彩色多普勒超声（ＣＤＳ）所探查的血流状态的关系,为提高ＭＲＡ诊断狭窄或闭塞的准确性提供依据。材料与方法：地３２例脑缺血性疾病患者（１３５支动脉）进行ＭＲＡ和ＣＤＳ的双盲法对照研究,同时以ＤＳＡ为对照标准,对８例患者进行ＭＲＡ、ＣＤＳ的对照分析。结果：在ＭＲＡ诊断的动脉狭窄中,ＣＤＳ表现为高速血流的占５２．５％,低束 流者占４７．５％;ＴＯＦ法ＭＲ     

成人型moya moya病的MR和MRA诊断(附6例分析)

目的：分析成人型moyamoya病的MRI和MRA影像特征。方法：回顾性分析6例经DSA证实的成人moyamoya病的MRI及MRA影像资料，采用GE1.5T超导型MR扫描系统行SE、FSE序旬MRI和三维时间飞跃法MRA。结果：成人型moyamoya病主要表现为多发腔隙性梗塞、脑萎缩，或并发脑实质出血、蛛网膜下腔出血。MRI显示闭塞的颅底大血管流空效应消失，兵脑和基底节区侧支循环流空信号增多，脑实质缺血或出血改变。MRA直接显示狭窄或闭塞的预内动脉（ICA）、大脑中动脉（MCA）、大脑前动脉（ACA）及侧支血管网。与DSA对比，MRA能够准确地显示闭塞或狭窄的大血管和代偿的不成形的弯延扭曲的侧支血管网。结论：MRI和MRA相结合可正确诊断moyamoya病，MRA是一种无创、短时、成功率和准确性高的检查方法，也可用于筛选可疑颅内动脉狭窄或闭塞的患者，避免或减少血管造影的次数。     

Prominent laterality of the posterior cerebral artery at three-dimensional time-of-flight MR angiography in M1-segment middle cerebral artery occlusion

BACKGROUND AND PURPOSE: Three-dimensional time-of-flight MR angiography (3D TOF MRA) often discloses prominent posterior cerebral artery (PCA) laterality in the setting of M1-segment middle cerebral artery (MCA) occlusion. We sought to analyze the implications of prominent PCA laterality at 3D TOF MRA. METHODS: We retrospectively reviewed 3D TOF MRA and digital subtraction angiography (DSA) findings in 25 patients (12 male, 13 female; mean age, 68.8 years [age range, 29-94 years]) with M1-segment occlusion. The observable laterality of the PCA, determined on the basis of 3D TOF MRA findings, was scored according to distal signal extent and compared with findings of collateral flow from the ipsilateral PCA via the leptomeningeal anastomosis (LMA) at DSA. Frequency of PCA laterality at 3D TOF MRA in patients and that in 56 healthy control subjects was also compared. RESULTS: The positive predictive value of PCA laterality for the existence of collateral flow was 99.9% and the negative predictive value 30.7%. The distal extent of ipsilateral PCA signal at 3D TOF MRA positively correlated with the grade of collateral flow from the PCA via the LMA (r = 0.802; P <.01). PCA laterality was significantly less common in control subjects (P <.01). CONCLUSION: Prominent PCA laterality at 3D TOF MRA in patients with M1-segment occlusion represents the existence of collateral flow from the PCA via the LMA.     

Redistribution of cerebropetal blood flow in patients with carotid artery stenosis measured non-invasively with fast cine phase contrast MR angiography

The purpose was to evaluate the blood flow redistribution in the neck vessels of patients with internal carotid artery (ICA) stenosis. Eighty-six patients with ICA stenosis underwent contrast-enhanced magnetic resonance angiography (CEMRA) and fast 2D phase contrast (2D-PC) sequence to measure the mean blood flow (MBF) of ICA, basilar artery (BA) and middle cerebral artery (MCA). CEMRA revealed 53 severe stenoses, 45 moderate stenoses and 3 occluded vessels. Patients with a unilateral severe ICA stenosis had a significantly reduced MBF of the ICA compared to the control group; the MBF reduction of the severely stenosed ICA was less conspicuous if associated with a controlateral severe stenosis. The MBF of the BA increased significantly in the presence of the bilateral severe ICA stenosis and in the ICA occlusion. The MBF of the MCA was unchanged in the presence of various degrees of ICA stenosis. Measurement of MBF with fast PC MRA permits cerebropethal blood flow assessment and gives additional information in grading ICA stenosis. The reduced MBF of a severe ICA stenosis has to be considered with caution since it depends also on the status of the controlateral ICA and may be considered a confident parameter only in case of unilateral carotid stenosis.     

Contrast-enhanced MR angiography of the supra-aortic vessels in 24 seconds: a feasibility study

A contrast-enhanced, gradient-echo 3D pulse sequence providing angiographic information in 24 s was tested in five healthy subjects and used prospectively in 21 patients for the investigation of the cervical arteries. Indications included suspected stenosis of the carotid (in 13), or vertebral arteries (in 1), carotid dissection (3), variants of the branches of the aortic arch (2) and extracranial carotid aneurysms (2). The results in all patients were compared with those of intra-arterial digital subtraction angiography (DSA). In patients with carotid stenosis, they were also compared with high-resolution 3D time-of-flight (TOF) MR angiography (MRA). Good quality MR angiograms of the neck vessels were obtained with the fast 3D sequence in 20 of the 21 patients. One claustrophobic patient was unable to co-operate. The degree of internal carotid artery (ICA) stenosis was graded correctly (compared to DSA) in 21 of 24 cases (87.5 %). Two mild stenoses were overestimated as moderate using the fast MR sequence and one high-grade stenosis was misdiagnosed as a complete occlusion. Carotid dissection was confirmed in one case and correctly excluded in two. Four extracranial ICA aneurysms in two patients, arterial variants and stenosis of the origin of the vertebral artery were correctly diagnosed using the contrast-enhanced MR angiogram. Three-dimensional TOF MRA was unsuccessful due to motion artefacts in half of the cases of ICA stenosis. Received: 6 August 1998 Accepted: 21 December 1998     

Intracranial vascular stenosis and occlusive disease: evaluation with CT angiography, MR angiography, and digital subtraction angiography

BACKGROUND AND PURPOSE: Although digital subtraction angiography (DSA) provides excellent visualization of the intracranial vasculature, it has several limitations. Our purpose was to evaluate the ability of helical CT angiography (CTA) to help detect and quantify intracranial stenosis and occlusion compared with DSA and MR angiography (MRA). METHODS: Twenty-eight patients underwent CTA, DSA, and 3D time-of-flight (TOF) MRA for suspected cerebrovascular lesions. All three studies were performed within a 30-day period. Two readers blinded to prior estimated or calculated stenoses, patient history and clinical information examined 672 vessel segments. Lesions were categorized as normal (0-9%), mild (10-29%), moderate (30-69%), severe (70-99%), or occluded (no flow detected). DSA was the reference standard. Unblinded consensus readings were obtained for all discrepancies. RESULTS: A total of 115 diseased vessel segments were identified. After consensus interpretation, CTA revealed higher sensitivity than that of MRA for intracranial stenosis (98% versus 70%, P < .001) and occlusion (100% versus 87%, P = .02). CTA had a higher positive predictive value than that of MRA for both stenosis (93% versus 65%, P < .001) and occlusion (100% versus 59%, P < .001). CTA had a high interoperator reliability. In 6 of 28 patients (21%), all 6 with low-flow states in the posterior circulation, CTA was superior to DSA in detection of vessel patency. CONCLUSION: CTA has a higher sensitivity and positive predictive value than MRA and is recommended over TOF MRA for detection of intracranial stenosis and occlusion. CTA has a high interoperator reliability. CTA is superior to DSA in the evaluation of posterior circulation steno-occlusive disease when slow flow is present. CTA results had a significant effect on patient clinical management.     

Collateral circulation imaging: MR perfusion territory arterial spin-labeling at 3T

BACKGROUND AND PURPOSE: Current knowledge of the collateral circulation remains sparse, and a noninvasive method to better characterize the role of collaterals is desirable. The aim of our study was to investigate the presence and distal flow of collaterals by using a new MR perfusion territory imaging, vessel-encoded arterial spin-labeling (VE-ASL).MATERIALS AND METHODS: Fifty-six patients with internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis were identified by sonography. VE-ASL was performed to assess the presence and function of collateral flow. The perfusion information was combined with VE maps into high signal-intensity-to-noise-ratio 3-colored maps of the left carotid, right carotid, and posterior circulation territories. The presence of the anterior and posterior collateral flow was demonstrated by the color of the standard anterior cerebral artery/MCA flow territory. The distal function of collateral flow was categorized as adequate (cerebral blood flow [CBF] ≥10 mL/min/100 g) or deficient (CBF <10 mL/min/100 g). The results were compared with those of MR angiography (MRA) and intra-arterial digital subtraction angiography (DSA) in cross table, and κ coefficients were calculated to determine the agreement among different methods.RESULTS: The κ coefficients of the presence of anterior and posterior collaterals by using VE-ASL and MRA were 0.785 and 0.700, respectively. The κ coefficient of the function of collaterals by using VE-ASL and DSA was 0.726. Apart from collaterals through the circle of Willis, VE-ASL showed collateral flow via leptomeningeal anastomoses.CONCLUSIONS: In patients with ICA or MCA stenosis, VE-ASL could show the presence, the origin, and distal function of collateral flow noninvasively.

The protective effect of collateral circulation influences final clinical outcomes for patients with hemodynamically significant arterial stenosis. The principal source of collateral flow of cerebral arteries is through the arteries of the circle of Willis. Secondary collateral pathways include the external carotid artery via the ophthalmic artery and leptomeningeal anastomoses at the brain surface. However, the size and patency of these arteries are quite variable.Doppler sonography is the most common tool used to investigate the presence of collateral flows. MR angiography (MRA) can be used for determining the collaterals through the circle of Willis. However, both sonography and MRA do not show leptomeningeal collateral pathways, distal collateral flows, or the actual contribution of collateral flow to brain perfusion. Intra-arterial digital subtraction angiography (DSA) shows the presence and distal arteries of the collateral pathways.¹ However, to visualize all the collateral pathways, this technique requires an invasive and selective 3-vessel approach and is typically not performed in patients with acute stroke or cerebral arterial stenosis. Therefore, a noninvasive method that demonstrates selectively angiographic information may be desired to investigate collateral blood flow.²In MR perfusion territory arterial spin-labeling (ASL),^3–7 blood in individual or groups of feeding arteries is tagged by using ASL methodology, and images are acquired that map the vascular distribution of those feeding arteries. Recently, vessel-encoded ASL (VE-ASL) MR imaging⁸ was introduced as a more time-efficient method for mapping multiple vascular territories. The aim of our study was to investigate the presence and distal flow of collateral blood supply by using the VE-ASL technique at 3T on patients with carotid stenotic disease.     

MR angiography in internal carotid artery dissection: improvement of diagnosis by selective demonstration of the intramural haematoma

We studied eight consecutive patients with clinical and intra-arterial angiographic (DSA) diagnosis of internal carotid artery (ICA) dissection to analyse the accuracy of MRA in dissections, using a new technique with presaturation pulses. Spin-echo images of the head were followed by three-dimensional time-of-flight (TOF) MRA at the site of the dissection, with and without a special caudal saturation pulse in addition to the cranial one. The accuracy of MRA was assessed in 64 segments of 16 ICA, all examined with DSA and MRA. High-signal intramural haematoma in the ICA at the level of the dissection was observed in all patients either on the maximal-intensity projection (MIP) reconstructions or on the partitions with this presaturation pulse technique. MRA had a sensitivity to detect dissected vessels of 100 %. Specificity for vessels correctly identified as not having a lesion was also 100 %. There was good correlation between DSA and MRA in demonstrating the site of the dissected ICA segment and the degree of stenosis. In only two cases was there overestimation of the degree of stenosis on the MIP reconstructions of the 3-D MRA. Received: 5 January 1998 Accepted: 30 April 1998     

下肢动脉硬化性闭塞症的DSA

目的：为给外科手术提供更多信息，对１０５例下肢动脉硬化性闭塞症患者作术前经动脉数字减影血管造影（ＩＡＤＳＡ）检查。材料和方法：经皮动脉穿刺插管后，用非离子型造影剂作腹主动脉下段至双胫腓动脉ＤＳＡ。结果：ＤＳＡ表现有：动脉狭窄、闭塞、血管壁溃疡，血管扭曲、延长，侧支形成。本组有８３例（７９．０％）双侧髂、股动脉呈对称性闭塞和／或狭窄。结论：下肢动脉硬化闭塞症好发于老年男性、常双侧发病，股髂动脉最易受累，ＩＡＤＳＡ能满足手术医生术前了解病变的需要，其对患者的创伤较小，可作为术前的常规检查方法