64层螺旋CT脑灌注成像和头颈部CT血管成像在颈内动脉和大脑中动脉狭窄和闭塞中的应用研究

目的评价64层螺旋CT脑灌注成像（CTP）和头颈部CT血管成像（CTA）检查对颈内动脉（ICA）及大脑中动脉（MCA）狭窄和（或）闭塞所致脑缺血的诊断价值。方法对69例经DSA证实为单、双侧ICA或MCA狭窄和（或）闭塞患者（病例组）及10名正常成年志愿者（对照组）分别进行64层螺旋CT头颅平扫、CTP和CTA检查，观察CTP成像特点，并对各组脑血流量（CBF）、脑血容量（CBV）、平均通过时间（MTT）和达峰时间（TTP）进行定量分析。结果CTA诊断为单侧ICA狭窄和（或）闭塞的患者17例中，5例仅累及分水岭区，10例同时累及MCA供血区和分水岭区。单侧ICA重度狭窄和（或）闭塞的灌注异常患者12例，非症状侧与症状侧的分水岭区CBF分别为（41±9）和（38±8）ml·100g^-1·min^-1，差异无统计学意义（t=2．08，P〉0．05）；MTT分别为（5．2±1．1）和（10．9±2．6）s，差异有统计学意义（t=7．24，P〈0．01）。CTA诊断为双侧ICA重度狭窄和（或）闭塞的13例中，双侧CTP均表现为MCA供血区加分水岭区灌注缺损。25例单侧MCA狭窄患者，4例灌注正常；17例脑灌注缺损区为MCA供血区，4例为MCA供血区加分水岭区。12例双侧MCA重度狭窄的患者，灌注损伤区均为MCA供血区加分水岭区。结论64层螺旋CT头颈部CTA联合应用脑CTP检查，为ICA和MCA狭窄和（或）闭塞的临床治疗提供了更为详尽客观的影像依据。     

320排CT全脑动态容积成像联合颈部CTA在评估慢性缺血性脑血管病中的应用

目的利用320排CT全脑动态容积成像联合颈部CT血管成像(CTA)探讨慢性脑缺血患者脑血流动力学变化及其与脑供血动脉狭窄的关系。方法前瞻性连续纳入88例单侧颈内动脉(ICA)或大脑中动脉(MCA)狭窄或闭塞患者行CT灌注(CTP)及CTA检查,评估ICA/MCA狭窄程度和Willis环完整性,计算MCA供血区及前后分水岭区相对灌注值,分析ICA/MCA狭窄程度与Willis环完整性(分型)、脑组织血流灌注各参数值的相关性。结果 1)88例中轻度狭窄12例、中度狭窄25例、重度狭窄24例、闭塞27例,其中单侧单纯ICA狭窄或闭塞48例,单侧单纯MCA狭窄或闭塞(M1段)40例;2)MCA区、前后分水岭区的rCBV、rMTT、rTTP值四组间差异均有统计学意义(均P0.05),rCBF四组间比较差异无统计学意义(均P0.05);3)MCA区的rCBF与狭窄率呈负性弱相关(r=-0.254,P=0.017),前后分水岭区的rCBF与狭窄率相关性无统计学意义(分别为r=-0.131,P=0.13;r=-0.2,P=0.062);狭窄率与大脑中动脉供血区、前分水岭区及后分水岭区的rCBV(r值分别为0.497、0.316、0.29,均为P0.01),rTTP(r值分别为0.691、0.619、0.593,均为P=0.000),rMTT(r值分别为0.695、0.514、0.508,均为P=0.000)呈正相关;4)重度狭窄、闭塞组中,不同Willis环分型与MCA区脑灌注参数间无相关性。结论 320排CT全脑动态容积成像联合颈部CTA检查能显示脑血流灌注参数的变化及相应头颈部供血动脉狭窄程度和Willis环结构。随着相应动脉狭窄率的增加,CBV、TTP、MTT值较对侧增加越大。狭窄程度与rTTP相关程度最高。     

头颈部CTA判断大脑中动脉区脑梗死患者供血动脉狭窄的价值

目的探讨头颈部计算机断层扫描血管成像（CTA）在判断大脑中动脉（MCA）区脑梗死患者血管狭窄程度以及与脑梗死程度的相关I生。方法对68例MCA区脑梗死患者进行头颈部CTA检查,分析受累血管狭窄程度及其与脑梗死程度的关系。结果68例中,颈内动脉（ICA）和MCA均正常者5例,单纯ICA狭窄共16例,其中轻度狭窄2例,中度狭窄4例,重度狭窄5例,闭塞5例;单纯MCA狭窄共41例,其中轻度狭窄6例,中度狭窄12例,重度狭窄18例,MCA闭塞5例;MCA合并ICA狭窄6例。ICA或MCA狭窄程度与脑梗死类型有关,狭窄程度越严重,梗死程度越严重（r=0.832,0．938,P〈0．05）。结论头颈部CTA在判断血管狭窄的同时,可预测患者脑梗死的程度,对脑梗死的临床诊断和治疗方案的选择具有重要的指导价值。     

MR灌注成像在颈内动脉和大脑中动脉狭窄与闭塞的应用研究

目的 探讨单侧颈内动脉（ICA）／大脑中动脉（MCA）慢性重度狭窄、闭塞患者的MR脑灌注成像（PWI）表现及其应用价值,分析PWI表现与动脉狭窄程度的关系。资料与方法 90例单侧ICA／MCA慢性重度狭窄或闭塞患者行MRPWI检查,计算出有关脑灌注参数图,包括相对脑血流量（rCBF）、相对脑血容量（rCBV）、相对平均通过时间（rMTT）和达峰时间（TTP）图,对PWI表现进行定性和定量分析,并作病变侧与对侧对比。62例单侧ICA重度狭窄或闭塞、28例单侧MCA重度狭窄或闭塞患者分别为重度狭窄和闭塞两组,对脑灌注结果与动脉狭窄程度的关系进行分析。结果 90例ICA／MCA慢性重度狭窄或闭塞患者,PWI均发现灌注异常,表现分为3期：l期3l例,表现为TTP、rMTY延迟,rCBF和rCBV正常;2期41例,表现为TTP、rMTT延迟,rCBF正常．rCBV轻度增高;3期18例,表现为TTP、rMTY延迟,rCBF、rCBV轻度下降。病变区rCBV、rMTY和TTP与对侧比较有显著性差异（P〈0．01）,PWI表现3期之间rCBF无显著差异（P〉0.05）,rCBV、rMTT、TTP均有显著性差异（P〈0．01）。PWI表现分期与ICA／MCA狭窄程度无明显关联性;rMTT、TTP值与ICA／MCA狭窄程度有关联性,闭塞组的rMTT、TTP值高于重度狭窄组（P〈0.01）。结论PWI检查能够显示单侧ICA／MCA慢性重度狭窄或闭塞患者脑血流动力学受损情况,区分局部低灌注的程度,对临床的诊断和治疗具有重要价值,而ICA／MCA狭窄程度不能完全预测脑血流动力学改变。     

CTP联合CTA对慢性脑缺血患者血流动力学的评价

目的：利用CT灌注（CTP）和CT血管成像（CTA）探讨慢性脑缺血患者脑血流动力学变化及其与脑供血动脉狭窄、血管性认知功能障碍之间的关系。方法：对55例临床拟诊为慢性脑缺血的患者行常规头颅CT平扫、CTP及CTA检查,应用简易智能状态检查（MMSE）量表评定受试者的智能状态。结果：根据平均通过时间（MTT）、达峰时间（TTP）图灌注延迟范围将灌注表现分为3型：Ⅰ型为大脑中动脉和/或大脑前动脉供血区广泛性低灌注22例;Ⅱ型为分水岭区局限性低灌注21例;Ⅲ型为灌注正常12例。颈内动脉（ICA）或大脑中动脉（MCA）的重度狭窄或闭塞所致脑灌注异常（Ⅰ、Ⅱ型）明显高于轻中度狭窄者（χ^2=29.49,P〈0.01）,Ⅲ型未见ICA或MCA的重度狭窄或闭塞。ICA或MCA狭窄程度与脑灌注异常之间呈正相关（Spearman′sr=0.74,P〈0.01）。脑灌注Ⅰ、Ⅱ型患者MMSE评分均低于正常值（P〈0.01）,且以Ⅰ型为著（P〈0.01）,Ⅲ型MMSE评分正常。结论：慢性脑缺血患者脑血流低灌注与ICA或MCA狭窄程度密切相关,在血管性认知功能障碍的发病机制中起着重要作用。     

VCT对头颈部血管狭窄与闭塞的诊断价值

目的 探讨64排螺旋CT(VCT)头颈部血管成像对头颈部血管慢性狭窄性病变的临床诊断价值.资料与方法 对62例可疑头颈部血管慢性狭窄性病变的患者应用CT血管成像(CTA)技术行头颈动脉成像检查,观察两侧椎动脉(VA)、颈内动脉(ICA)以及大脑前动脉(ACA)、大脑中动脉(MCA)和大脑后动脉(PCA).对所有图像行曲面重组(CPR)、容积再现(VR)、最大密度投影(MIP)及多平面重组(MPR)处理.结果 62例中头颈部CTA未见异常19例,发现血管异常43例.其中VA狭窄18支,闭塞7支;ICA狭窄30支,闭塞7支;ACA和MCA狭窄11支,闭塞2支,PCA发育不良2支.烟雾病2例,脑内动静脉畸形2例.血管起源变异4例.结论 VCT头颈部血管成像能准确显示头颈部血管正常解剖与异常改变,二维与三维图像相结合对头颈部血管狭窄或闭塞诊断和治疗方案的制定具有指导意义.     

全脑CTP及动态CTA评估单侧大脑中动脉狭窄或闭塞患者侧支循环状态及预后的价值

目的探讨全脑CT灌注(CTP)及动态CT血管成像(CTA)在大脑中动脉(MCA)狭窄或闭塞患者侧支循环评估中的应用。方法选取我院收治的102例MCA狭窄或闭塞患者的临床资料,均行CTP结合动态CTA检查。统计CTA图像下MCA狭窄程度及MCA狭窄或闭塞侧与对侧脑灌注参数及侧支循环良好一端与侧支循环差一端的灌注参数相对值。结果102例单侧MCA狭窄或闭塞患者均得到了良好的CTA图像,其中46例完全闭塞患者,占45.1%,40例重度狭窄患者,占39.2%,16例中度狭窄患者,占15.7%;动态CTA图像显示MCA狭窄或闭塞一侧侧支循环良好的患者65例,占63.7%,随访3个月患者临床预后良好;侧支循环差的患者37例,占36.3%,随访患者临床预后差,生活质量差;相较于对侧,MCA狭窄或闭塞患者闭塞侧TTP、MTT明显更高,而CBF、CBV明显更低,差异均有统计学意义(均P<0.05);相较于侧支循环良好,MCA狭窄或闭塞一侧侧支循环差者rCBF、rCBV明显更低(均P<0.05),两者rTTP、rMTT差异无统计学意义(P>0.05)。结论全脑CTP及动态CTA可很好地评估一侧MCA闭塞或狭窄情况及侧支循环情况。     

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。     

头颈部CTA对糖尿病性脑梗死的鉴别诊断价值

目的 探讨头颈部CT血管成像(CTA)对糖尿病性脑梗死的鉴别诊断价值。方法 选取我院54例合并有糖尿病的脑梗死患者作为观察组,并按1:1比例选取同期收治54例未合并有糖尿病的脑梗死患者作为对照组,对所有患者行CTA检查,观察两组患者脑梗死类型、动脉血管狭窄程度以及颅内及颅外血管狭窄或闭塞分布情况。结果 观察组患者多发性脑梗死发生率高于对照组,差异有统计学意义(P <0.05)。观察组患者头颈部动脉、颅内动脉及侧支循环狭窄程度均高于对照组,差异有统计学意义(P <0.05)。两组患者颈内动脉颅段、大脑前动脉(ACA)、大脑中动脉(MCA)及头臂动脉、颈总动脉分叉部及颈内动脉颅外段血管狭窄或闭塞发生率对比,差异无统计学意义(P> 0.05);但观察组大脑后动脉(PCA)、椎动脉颅内段、基底动脉及椎动脉颅外段血管狭窄或闭塞发生率均高于对照组,差异有统计学意义(P<0.05)。观察组患者头颈部血管钙化斑块及混合斑块占比均高于对照组,差异具有统计学意义(P <0.05)。结论 糖尿病性脑梗死患者动脉血管狭窄程度更为严重,动脉狭窄部位多位于后循环,并以钙化斑块及混合斑...     

64排128层CT血管减影技术对头颈部血管狭窄或闭塞病变的诊断价值

目的探讨64排128层CT血管减影技术在头颈部血管狭窄和闭塞病变中的应用价值。 方法92例怀疑颅内外动脉狭窄或闭塞患者行64排128层CT血管减影检查,使用VR、Reformat、CPR等软件分析各血管狭窄或闭塞情况、斑块性质及狭窄与脑梗死间的关系。 结果65例患者颅内外血管均可见不同程度的狭窄或闭塞,以中、重度狭窄为主;113支血管有附壁粥样硬化斑块形成,钙化斑块、血管腔及硬化斑块CT值间差异有统计学意义(P<0.01);梗死侧颈动脉、大脑中动脉狭窄发生率与非梗死侧比较差异均有统计学意义(P均<0. 05)。 结论64排CT血管减影技术能够准确地评估血管狭窄和斑块性质,为临床治疗方法的选择提供有价值的信息。     

High-Resolution Intracranial Vessel Wall MRI Findings Among Different Middle Cerebral Artery Territory Infarction Types

ObjectiveIntracranial atherosclerotic stroke occurs through various mechanisms, mainly by artery-to-artery embolism (AA) or branch occlusive disease (BOD). This study evaluated the spatial relationship between middle cerebral artery (MCA) plaques and perforating arteries among different MCA territory infarction types using vessel wall magnetic resonance imaging (VW-MRI).Materials and MethodsWe retrospectively enrolled patients with acute MCA infarction who underwent VW-MRI. Thirty-four patients were divided into three groups according to infarction pattern: 1) BOD, 2) both BOD and AA (BOD-AA), and 3) AA. To determine the factors related to BOD, the BOD and BOD-AA groups were combined into one group (with striatocapsular infarction [BOD+]) and compared with the AA group. To determine the factors related to AA, the BOD-AA and AA groups were combined into another group (with cortical infarction [AA+]) and compared with the BOD group. Plaque morphology and the spatial relationship between the perforating artery orifice and plaque were evaluated both quantitatively and qualitatively.ResultsThe plaque margin in the BOD+ group was closer to the perforating artery orifice than that in the AA group (p = 0.011), with less enhancing plaque (p = 0.030). In the BOD group, plaques were mainly located on the dorsal (41.2%) and superior (41.2%) sides where the perforating arteries mainly arose. No patient in the AA group had overlapping plaques with perforating arteries at the cross-section where the perforator arose. Perforating arteries associated with culprit plaques were most frequently located in the middle two-thirds of the M1 segment (41.4%). The AA+ group had more stenosis (%) than the BOD group (39.73 ± 24.52 vs. 14.42 ± 20.96; p = 0.003).ConclusionThe spatial relationship between the perforating artery orifice and plaque varied among different types of MCA territory infarctions. In patients with BOD, the plaque margin was closer and blocked the perforating artery orifice, and stenosis degree and enhancement were less than those in patients with AA.     

颅内高信号血管征与颈内或大脑中动脉重度病变患者发生脑缺血事件相关

目的:探讨颅内高信号血管征(HVS)与颈内动脉或大脑中动脉重度病变患者发生症状性脑缺血事件之间的相关性及其危险因素.方法:搜集颈内动脉或大脑中动脉重度病变患者96例,依据头颅磁共振液体衰减恢复信号(FLAIR)结果判断HVS,按照Alberta卒中项目早期CT评分(mASPECTS)标准对HVS进行评分(HVS-mAS...     

颈动脉狭窄或闭塞患者数字记忆的功能磁共振成像研究

目的:探讨左侧颈内动脉/大脑中动脉狭窄和闭塞患者与正常人数字工作记忆的激活脑区差异及其记忆障碍的脑加工机制。方法:对12例左侧颈动脉狭窄/闭塞患者(其中左侧颈内动脉狭窄4例,左侧颈内动脉闭塞2例,左侧大脑中动脉狭窄5例,左侧大脑中动脉闭塞1例,24例正常对照组进行数字记忆任务的功能磁共振成像,采用AFNI软件进行数据分析和脑功能区活动图像。结果:左侧颈内动脉/大脑中动脉狭窄和闭塞患者的反应时间较对照组显著延长(P0.05),正确率较对照组明显降低(P0.05)。脑激活图显示数字工作记忆的编码期、保持期、提取期患者组的脑激活明显少于正常对照组,而且脑激活的左侧半球优势减弱,右侧半球出现代偿性激活,其中提取期最为明显。结论:左侧颈动脉狭窄/闭塞患者数字记忆任务的脑激活区存在损害,功能磁共振成像研究能为早期诊断认知障碍提供影像学依据。     

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.     

容积穿梭80 mm CT脑灌注成像及动态四维CT血管成像诊断颈内动脉系统血管狭窄和闭塞

目的 探讨利用容积穿梭扫描模式(volume shuttle)的80 mm CTP)及80 mm动态4D-CTA诊断大脑Willis环血管狭窄或闭塞.方法 55例大脑中动脉(MCA)或颈内动脉(ICA)重度狭窄或闭塞患者,行CT平扫、脑CTP和头颈部CTA检查,CTP检查获得脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)、达峰时间(TTP)等参数,同时获得80 mm(0.625 mm×128)扫描覆盖范围内动态4D-CTA.采用K Independent Samples分析ICA或MCA狭窄或闭塞者脑血流灌注参数CBF、CBV、MTT、TTP.结果 40例单侧MCA或ICA重度狭窄或闭塞患者中4例脑血流灌注未见显著异常改变,36例患者TTP和MTT均发现与临床症状相对应的灌注延迟区,病变侧MTT(7.18±1.34)s、TTP(19.65±1.81)s与健侧MTT(5.22±1.14)s、TTP(17.62±1.65)s比较,差异有统计学意义(X~2值分别为30.833、25.817,P值均<0.017);CBV、CBF未见明显异常.15例双侧MCA或ICA重度狭窄或闭塞患者,5例责任病灶侧与非责任病灶侧比较,脑血流灌注未见明显差异.10例责任病灶侧与非责任病灶侧比较,可见明显的脑血流灌注异常区,TTP和MTT较非责任病灶侧延迟,责任病灶侧 CBF(42.85±6.09)ml·100 g~(-1)·min~(-1)、CBV(2.63±0.42)ml·100 g~(-1)、MTT(11.27±1.43)s、TTP(21.07±1.44)s和对照组CBF(71.20±6.30)ml·100 g~(-1)·min~(-1)、CBV(2.29 ±0.15)ml·100 g~(-1)、MTT(3.38±0.61)s、TTP(17.64±1.70)s比较,差异具有统计学意义(X~2值分别为17.314、5.913、17.334、13.834,P值均<0.017).应用容积穿梭扫描模式获得80 mm动态Willis环4D-CTA图像,27例单侧MCA重度狭窄或闭塞患者中右侧MCA狭窄患者13例,左侧MCA狭窄患者9例;单侧MCA闭塞患者5例,其中右侧1例,左侧4例.9例双侧MCA重度狭窄或闭塞患者4D-CTA图像显示双侧MCA狭窄.4D-CTA图像与常规CTA、DSA显示Willis环血管狭窄或闭塞结果一致.结论 64层CT容积穿梭扫描模式可同时获得80 mm脑血流灌注和80 mm动态Willis环4D-CTA,对MCA或ICA狭窄或闭塞不仅能确定脑灌注异常范围,而且能够进行病因诊断,指导临床医师选择治疗方案及评价疗效,有广泛的临床应用前景.     

Changes in cerebral hemodynamics after carotid stenting of symptomatic carotid artery

Purpose

To evaluate changes in cerebral hemodynamics after carotid stenting of symptomatic carotid artery in the patients who underwent ischemic stroke caused by carotid artery stenosis.

Methods

Twenty patients with unilateral symptomatic carotid artery stenosis received brain computer tomography perfusion (CTP) scan a week before and a week after carotid artery stenting. Three absolute values including mean transit time (MTT), cerebral blood volume (CBV), and cerebral blood flow (CBF) were acquired and analyzed by use of the post-processing software. Six vascular territories such as ACA territory, MCA territory, PCA territory, basal ganglia, watershed between ACA and MCA territory (frontal watershed), watershed between MCA and PCA territory (posterior watershed) were chosen for comparison. Relative parameter values were defined as rCBF (relative CBF), rCBV (relative CBV), rMTT (relative MTT) through comparing absolute values in symptomatic hemispheres to absolute values in asymptomatic hemispheres. The relative perfusion parameter values before treatment were compared with post-treatment values. These analyses were performed by using the paired t test.

Results

The mean rMTT decreased significantly in ACA territory, MCA territory and two watershed after treatment, while the mean rCBF increased significantly in those areas after treatment. But the mean rCBV had no significant changes in all six vascular territories. In PCA territory, all the parameters had no significant changes.

Conclusion

Carotid artery stenting yields satisfactory cerebral perfusion in ACA territory, MCA territory, basal ganglia and two watersheds.     

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.