Measurements of diagnostic examination performance and correlation analysis using microvascular leakage,cerebral blood volume,and blood flow derived from 3T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in glial tumor grading

Introduction  

To assess the diagnostic accuracy of microvascular leakage (MVL), cerebral blood volume (CBV) and blood flow (CBF) values derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC-MR imaging) for grading of cerebral glial tumors, and to estimate the correlation between vascular permeability/perfusion parameters and tumor grades.     

Using relative cerebral blood flow and volume to evaluate the histopathologic grade of cerebral gliomas: preliminary results

OBJECTIVE: Relative cerebral blood flow has rarely been studied as part of the preoperative assessment of tumor grade, although relative cerebral blood volume is known to be useful for this assessment. The purpose of our study was to determine the usefulness of relative cerebral blood flow in assessing the histopathologic grade of cerebral gliomas. SUBJECTS AND METHODS: MR imaging was performed in 17 patients with proven cerebral gliomas (11 high-grade gliomas and six low-grade gliomas), using a first-pass gadopentetate dimeglumine-enhanced T2-weighted echoplanar perfusion sequence. The perfusion data were deconvoluted with an arterial input function, using singular value decomposition to obtain a color map of relative cerebral blood volume and flow; the relative cerebral blood volume and flow ratios were expressed relative to values measured in the contralateral white matter. The Wilcoxon's rank sum test was performed to test the difference between the mean of the relative cerebral blood volume (or flow) ratio in high-grade gliomas and that in low-grade gliomas. Receiver operating characteristic curve analysis was used to evaluate the association between the relative cerebral blood volume (or flow) ratio and the grade of the glioma, as well as to calculate the relative cerebral blood volume and flow ratio cutoff value permitting discrimination between high- and low-grade gliomas. The correlation between relative cerebral blood volume and flow ratios was evaluated using Spearman's rank correlation analysis. We also made a qualitative assessment regarding the match or mismatch of areas of maximal contrast enhancement with the areas of highest color perfusion maps. RESULTS: The mean of the relative cerebral blood volume ratio was 4.91 in the high-grade gliomas and 2.00 in the low-grade gliomas. The mean relative cerebral blood flow ratio was 4.82 in the high-grade gliomas and 1.83 in the low-grade gliomas. A significant difference in each relative cerebral blood volume and flow ratio was found between the high- and low-grade gliomas (Wilcoxon's rank sum test, p < 0.05). Both the relative cerebral blood volume and flow ratios strongly matched the grade of the glioma, but the difference between the two areas was not significant (receiver operating characteristic curve analysis, p > 0.05). The desired cutoff value was 2.93 in the relative cerebral blood volume ratio and 3.57 in the relative cerebral blood flow ratio. Additionally, there was a strong correlation between the relative cerebral blood volume and flow ratios (Spearman's rank correlation coefficient = 0.762; p < 0.05). There was frequent mismatch (33%) between the qualitative assessment of the contrast-enhanced T1-weighted MR images and the perfusion maps. CONCLUSION: First-pass gadopentetate dimeglumine-enhanced T2-weighted echoplanar perfusion MR imaging is useful for the preoperative assessment of tumor grade. A relative cerebral blood flow ratio, in addition to a relative cerebral blood volume ratio, can be a useful tool in the evaluation of the histopathologic grade of cerebral gliomas.     

Can cerebrovascular reactivity be assessed by dynamic susceptibility contrast-enhanced MRI?

The acetazolamide (ACZ) test is performed to evaluate the decrease in cerebral perfusion pressure (CPP) by investigation of vasomotor reactivity (VMR). Our aim was to study cerebral blood flow and blood volume changes induced by the ACZ test in healthy control subjects using dynamic susceptibility contrast-enhanced gradient-echo MRI (DSC-MRI). A FLASH sequence was used to produce susceptibility-weighted images during an intravenous injection of 0.1 mmol/kg gadopentetate dimeglumine (Gd-DTPA). After the first dynamic study, 1 g acetazolamide was given intravenously and 10 min later a second bolus of Gd-DTPA was injected. Using the indicator-dilution theory, relative cerebral blood volume and relative cerebral blood flow were estimated. In healthy subjects the ACZ test induced a significant increase in relative blood volume (from 80.5 ± 10.7 to 113.4 ± 11.9) and relative blood flow (from 5.73 ± 0.96 to 7.5 ± 0.97), symmetrically in the cerebral hemispheres. This approach might be promising in the understanding of cerebral haemodynamics in patients with vascular disorders. Received: 14 October 1996 Accepted: 2 May 1997     

Evaluation of peri-infarcted hypoperfusion with T2*-weighted dynamic MRI

The purpose of this study was to evaluate cerebral perfusion with T2*-weighted dynamic MRI in the area around the infarcted core. We examined seven patients with subacute cerebral infarction. After bolus injection of gadopentetate dimeglumine, a series of gradient-echo images were recorded in a selected slice. From these images, concentration-time curves were created on a region-of-interest (ROI) basis around infarction for calculating relative regional cerebral blood volume (rrCBV). Brain perfusion single photon emission computed tomography (SPECT) study also was performed with intravenous injection of ¹²³I-labeled N-isopropyl-p-iodoamphetamine (¹²³I-IMP). All patients showed prolonged signal decrease in the area around the infarcted core. ROI analysis showed significantly increased rrCBV compared to the normal side (P < .01, paired t test). The ¹²³I-IMP SPECT study showed that these areas had decreased cerebral blood flow. These findings suggest compensatory vascular dilatation due to decreased perfusion pressure. T2*-weighted dynamic MRI is a useful method for detecting compensatory vasodilatation of ischemic insult in the peri-infarcted area.     

Iron-induced susceptibility effect at the globus pallidus causes underestimation of flow and volume on dynamic susceptibility contrast-enhanced MR perfusion images

BACKGROUND AND PURPOSE: Age-related iron accumulation in extrapyramidal nuclei causes T2 shortening, which may result in decreased signal intensity in these areas on MR images. Because the dynamic susceptibility contrast-enhanced technique uses heavily T2*- or T2-weighted images, the iron-induced susceptibility may have direct impact on perfusion imaging. The purpose of this study was to assess the effect of iron-induced susceptibility on the calculated perfusion parameters. The difference of this effect between gradient-echo and spin-echo sequences was also assessed. METHODS: Dynamic susceptibility contrast-enhanced MR perfusion imaging data of 12 patients were used for this study. Perfusion images were obtained using a single shot spin-echo echo-planar imaging sequence in seven patients and a gradient-echo echo-planar imaging sequence in five patients. Region of interest measurements of relative cerebral blood flow, relative cerebral blood volume, and mean transit time were obtained at various parts of the gray matter, including the globus pallidus, putamen, caudate nucleus, thalamus, and cerebral cortex of temporal, frontal, and occipital lobes. The baseline signal intensity on the source images and the magnitude of signal change (DeltaR2* or DeltaR2) were also assessed. RESULTS: The globus pallidus had statistically significantly lower values of relative cerebral blood flow, relative cerebral blood volume, baseline signal intensity, and magnitude of signal change compared with other parts of the gray matter for both gradient-echo and spin-echo sequences (P <.05). Underestimations of these values were more prominent for the gradient-echo than for the spin-echo sequence. Little variance in the measured mean transit time was noted. CONCLUSION: Iron-induced susceptibility effect may lead to underestimation of relative cerebral blood flow and relative cerebral blood volume in the basal ganglia.     

Reproducibility of quantitative CT perfusion imaging.

The ability to demonstrate regions of abnormal cerebral blood flow in the setting of acute stroke is of diagnostic and prognostic importance. It may also influence therapeutic strategies. The advantage of CT perfusion imaging is its ability to give quantifiable measurements of cerebral blood flow on any modern CT machine without the need to buy specialized equipment. The aim was to assess day-to-day variability of values of cerebral blood volume obtained with this technique. Seven patients with cerebral gliomas were studied using dynamic CT perfusion imaging on two occasions, approximately 24 h apart to reduce variability from diurnal variations. Regions of interest were produced in predominately middle cerebral artery locations in both hemispheres on the first and second CT perfusion studies. Absolute values for cerebral blood flow were produced for these regions and were correlated with flows obtained in the same regions of interest on the follow-up study. The Pearson correlation coefficient obtained was 0.884. CT perfusion imaging is easily performed on conventional modern CT equipment and demonstrates little variability in measures of absolute cerebral blood flow within individuals when studied on two occasions within 24 h.     

CT脑组织血流灌注成像方法的研究

目的 探讨CT灌注成像方法在颅脑疾病诊断中的初步临床应用。方法 采用Siemens Plus4和Perfusion CT/VA 10A扫描灌注系统,对8例进行常规扫描,然后选定基底节区层面做快速注药后的动态CT检查,对比剂为优维显300（300mgI/ml),注射速度10ml/s,剂量50ml,经高压注射器注射的同时进行扫描,共扫描32层。经后处理获得一系列反映不同时相的脑血流灌注图,然后进行综合分析。结果 4例正常脑血流灌注图清晰,脑灰白质交界分明、对称,染色均匀;2例缺血灌注图经伪彩染色后,病灶显示更加直观、清晰;2例肿瘤灌注图显示单发转移瘤异常供血血管、水肿区和过度灌注区。结论 快速注射对比剂和选用上矢状窦为参照血管计算脑血容量是获得高质量灌注图像的保证,为实现CT脑组织血流灌注的定量研究提供了新的方法。     

Measuring blood volume and vascular transfer constant from dynamic, T(2)*-weighted contrast-enhanced MRI.

Dynamic, contrast-enhanced MRI (deMRI) is increasingly being used to evaluate cerebral microcirculation. There are two different approaches for analyzing deMRI data. Intravascular indicator dilution theory has been used to estimate blood volume (and perfusion), usually from T(2)- or T(2) (*)-weighted images of the first pass of the bolus. However, the theory assumes that the tracer (i.e., contrast agent) remains intravascular, which is often not the case when the blood-brain barrier (BBB) is damaged. Furthermore, the method provides no information on the vascular transfer constant. Pharmacokinetic modeling analyses of T(1)-weighted images after first pass do give values of the vascular transfer constant and the volume of the extravascular, extracellular space (EES), but they generally are unable to give estimates of blood volume. In this study we apply pharmacokinetic modeling to dynamic T(2) (*)-weighted imaging of the first pass of a tracer bolus. This method, which we call first-pass pharmacokinetic modeling (FPPM), gives an estimate of the blood volume, vascular transfer constant, and EES volume. The method was applied to a group of 26 patients with surgically proven tumors (10 glioblastomas multiforme (GBMs), six lymphomas, and 10 meningiomas). The measurements of the blood volume and transfer constant were consistent with the known physiology of these tumors.     

CT脑灌注与血管造影在急性脑梗死中的临床应用

目的:探讨64层螺旋CT脑灌注成像和脑血管造影技术在急性期脑梗死中的应用价值。方法:应用PhilipsBrilliance CT 64,对30例发病12h内急性脑缺血患者行CT平扫、CT脑灌注成像(CTP)和CT血管造影(CTA)检查。分析平扫及灌注成像表现,计算出缺血区脑血流参数,包括:脑血容量图(CBV)、血流量图(CBF)、对比剂平均通过时间(MTT)和对比剂峰值时间(TTP),与对侧相应区灌注参数进行比较,并重建颈段和脑内动脉CTA图像。所有病例在发病后3~14天复查CT平扫。结果:30例患者中16例头颅平扫发现早期脑梗死征象,14例常规平扫未发现异常,而CTP均发现灌注异常区。CTP表现为CBF及CBV减低、MTT及TTP延迟;患侧CBF、MTT、TTP与对侧差异有显著性意义(P<0.01),患侧CBV与对侧差异无显著性意义(P>0.01)。重建CTA图像显示16例一侧颈内动脉狭窄,8例一侧大脑中动脉狭窄(其中1例伴大脑后动脉狭窄、左侧后交通动脉闭塞);4例左侧大脑中动脉闭塞,2例左侧颈内动脉闭塞。结论:CTP能够早期、及时、准确地反映缺血部位及程度,预测半暗带;CTA可以显示病变血管的部位和程度;联合应用两者,对早期诊断急性脑缺血和指导治疗有重要价值。     

微机辅助CT脑灌注成像以及定量测量

目的：报告微机辅助CT脑灌注成像以及定量测量方法。方法：以PentiumⅡ300MHz微处理器，128MB内存，16MB显存，6G硬盘PC机和Windows98第2版为平台，用VissualC 为开发语言，根据中心容积定理，利用动态CT图像分析并计算脑血流动力学的有关参数，包括脑血流量（cerebral blood flow,CBF)，脑血容量（cerebral blood volume,CBV),平均通过时间（mean transit time,MTT)和峰值时间（time to peak,TTP)等。最后，将脑血流动力学数据根据色阶分别处理成脑血流量图（mapping of CBF)，脑血容量图（mapping of CBV)，平均通过时间图（mapping of MTT)和峰值时间图（mapping of TTP)。结果：动态增强CT图像经软件处理后可以在微机上显示脑组织的CBF，CBV，TTP和MTT灌注原始图像以及分割颅骨，皮下组织和脑室后的图像。急性脑缺血患者在MR T1加权像，T2加权像，平扫CT以及增强CT未显示的责任病灶，脑CT灌注图像可以清楚显示脑血流动力学的异常。结论：微机辅助CT脑灌注成像简单铁行，可显示常规CT和MR无法发现的早期脑缺血区的血流异常。与MR灌注成像相比更适用于急诊检查。     

兔VX2软组织肿瘤MSCT灌注成像与病理对照研究

目的对兔VX2软组织肿瘤进行MSCT灌注成像与病理对照研究,探讨MSCT灌注成像在软组织肿瘤中的应用价值。材料与方法8只新西兰大白兔,双侧大腿近段注射VX2肿瘤组织悬液0．1ml,分别于肿瘤组织接种后第14、21d行CT平扫和灌注扫描,扫描图像经AW4．0工作站处理,计算并分析灌注图像和灌注参数,包括血流量(BF)、血容量(BV)、平均通过时间(MTT)和表面通透性(PS)。随后处死荷瘤兔,取出肿瘤行病理组织学检查,对其微血管密度(micro vascular density,MVD)进行测定,分析MSCT。功能参数图像与肿瘤MVD之间的关系。结果所有兔大腿VX2肿瘤组织BF、BV、PS值明显高于正常肌肉组织,且与肿瘤MVD呈正相关;而MTT值则明显低于正常肌肉组织,与肿瘤MVD无明显相关性。结论MSCT灌注成像是一种准确且相对简单、便捷的定量评估软组织肿瘤性病变血流灌注状态的功能成像方法。     

CT灌注成像在胰腺肿瘤诊断中的应用价值

目的:探讨胰腺肿瘤的CT灌注成像(CTPI)特征,评价CTPI在胰腺肿瘤诊断中的价值.方法:对50例胰腺肿瘤患者和45例非胰腺疾病患者行CTPI,选择获得良好灌注图像者共76例,其中胰腺肿瘤患者44例和非胰腺病变患者32例.测量ROI的血流量(BF)、血容量(BV)、达峰时间(TTP)和表面通透性(PS)的值,并进行统...     

Dynamic 3D-CT angiography

BACKGROUND AND PURPOSE: 3D-CT angiography (3D-CTA), a vessel-cast technique, is useful in the diagnosis of patients with brain lesions and cerebrovascular disease. However, it provides no information on blood-flow dynamics. Therefore, we developed a new technique, dynamic 3D-CTA (d3D-CTA), that yields 3D images of the vasculature and allows assessment of the hemodynamics and of the cerebral perfusion. METHODS: We subjected 12 patients to d3D-CTA; 7 had brain tumors, 4 had arteriovenous malformations (AVMs), and 1 presented with cervical internal carotid artery occlusion. d3D-CTA was performed with a multidetector-row CT scanner with 64 detectors; the parameters were 0.5-mm section thickness, 0.5 seconds per rotation, 135 kV, and 150 mA. Contrast medium (total volume, 30-35 mL) was injected at 6-7 mL/s; scanning was started after a 5-second delay. Scans were generated with volume-rendering reconstruction and displayed in cine mode. RESULTS: We succeeded in obtaining d3D-CTA scans in all cases. The scans yielded 3D information on the vascular structures and hemodynamics and on the status of the cerebral perfusion. CONCLUSION: d3D-CTA facilitates the acquisition of information on the vascular and cerebral dynamic blood flow on 3D-CTA images. Despite the relatively high radiation exposure and contrast injection speed and its limited scan range, this technique is useful for the diagnosis of patients with brain tumors or cerebrovascular disease and for treatment planning.     

Perfusion MRI of infarcted and noninfarcted brain tissue in stroke: a comparison of conventional hemodynamic imaging and factor analysis of dynamic studies

RATIONALE AND OBJECTIVES: To investigate the hemodynamics of infarcted and noninfarcted regions of the brain in patients with stroke secondary to a complete middle cerebral artery occlusion. Also, to compare factor analysis, a novel method of analyzing perfusion-weighted images, with more conventional techniques. METHODS: Twenty-two patients with complete unilateral occlusion of the middle cerebral artery were examined by T1-weighted, contrast-enhanced, perfusion-weighted imaging, diffusion-weighted imaging, and magnetic resonance angiography. Quantitative cerebral blood volume (CBV), cerebral blood flow (CBF), and time-to-peak-intensity (TTP) images were generated. Factor analysis of dynamic studies (FADS) was used to generate "early" and "late" images. The hemodynamic parameters for the infarcted and noninfarcted regions of the occluded territory were compared with those for the brain territory on the nonoccluded side. RESULTS: Three regions were shown: (1) Normal tissue on the unaffected side; (2) an infarcted region, which was characterized by reduced CBV, CBF, and early FADS values with increased TTP values; and (3) a noninfarcted region with reduced early FADS and increased late FADS and TTP values compared with the normal region. Cerebral blood volume and CBF values were not reduced significantly in the noninfarcted region. CONCLUSIONS: The differences in parameters such as TTP, CBV, and CBF are significant, and it is necessary to use more than one parameter when interpreting magnetic resonance imaging perfusion data. Factor analysis of dynamic studies provides additional information to conventional methods of analyzing perfusion data.     

磁共振脑血流灌注的影像及定量分析

目的 应用对比增强磁共振脑血流灌注成像,研究不同病理状态下脑组织的血液动力学变化。方法 采用对Ｔ２＾＊敏感的平面回波自由衰减序列（ＥＰＩ－ＦＩＤ）,对４５例因性因管病、１１例其他脑血管病、４例脑肿瘤和４例脑炎患者进行了注射对比剂后的血流灌注加权成像（ＰＷＩ）,分析脑血流灌注图,并定量地研究脑组织的血液动力学变化。结果 磁共振脑血流灌注图和定量分析发现５４个病例的脑组织有异常的血液动力学变化;ＰＷＩ     

16层螺旋CT胰腺癌灌注研究

目的探讨正常胰腺和胰腺癌的MSCT灌注成像特征。方法30例无胰腺疾病的患者和16例经病理证实的胰腺癌患者,采用16层螺旋CT进行灌注扫描,分别测量30例正常胰腺组织和16例胰腺癌肿瘤组织及周围正常胰腺组织的血流量(BF)、血容量(BV)、平均通过时间(MTT)和表面通透性(PS)值,并进行分析。结果胰腺CT灌注的各项指标个体差异较大,但正常胰腺组织和癌周相对正常的胰腺组织的BF、BV、PS和MTT的平均值差异无显著性意义。正常胰腺组织和癌周相对正常胰腺组织的BV、BF高于胰腺癌组织,PS低于胰腺癌组织。胰腺癌周围相对正常胰腺组织与胰腺癌组织PS、BV和BF前后配对t检验差异更加明显。结论CT灌注成像技术对胰腺癌诊断具有重要的提示意义。     

Dynamic contrast-enhanced T2*-weighted MRI in patients with cerebrovascular disease

Our purpose was to investigate the potential of dynamic susceptibility contrast-enhanced MRI in assessing regional haemodynamics in patients with cerebrovascular disease. T2^*-weighted FLASH sequences were performed on a control group of 10 healthy subjects, 13 patients with unilateral stenosis or occlusion of the internal carotid artery and 6 patients with acute onset of neurological symptoms, the observed signal intensities being converted into concentration-time curves. A gamma-variate function was fitted to the measured concentration-time curves to eliminate effects of tracer recirculation. In each patient the two cerebral hemispheres were compared and the difference between the mean transit times and the percental change of the regional cerebral blood volume, calculated for each side. Patients with haemodynamically significant unilateral carotid obstruction can be divided into two subgroups: those with good and those with poor collateral supply. Patients with good collateral supply had a slight but not statistically significant increase in mean transit time and cerebral blood volume on the diseased side, whereas those with poor collaterals had a significant increase compared with the control group. In patients with acute onset of neurological symptoms perfusion maps clearly demonstrated the disturbed perfusion at a time when T2-weighted images were still normal. Perfusion imaging is a reliable and noninvasive method of assessing changes in cerebral perfusion in patients with unilateral carotid stenosis. This MR technique permits monitoring of haemodynamic changes during therapy and thus may become an alternative to SPECT and PET scanning. In patients with acute occlusion of a cerebral artery, perfusion imaging reveals the entire perfusion deficit before conventional MRI and thus allows early intervention. Received: 10 April 1996 Accepted: 14 June 1996     

Measurement of brain perfusion,blood volume,and blood‐brain barrier permeability,using dynamic contrast‐enhanced T1‐weighted MRI at 3 tesla

Assessment of vascular properties is essential to diagnosis and follow‐up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood‐brain permeability from dynamic T₁‐weighted imaging of a bolus of a paramagnetic contrast agent passing through the brain. The methods are applied in patients with brain tumors and in healthy subjects. Perfusion was estimated by model‐free deconvolution using Tikhonov's method (gray matter/white matter/tumor: 72 ± 16/30 ± 8/56 ± 45 mL/100 g/min); blood volume (6 ± 2/4 ± 1/7 ± 6 mL/100 g) and permeability (0.9 ± 0.4/0.8 ± 0.3/3 ± 5 mL/100 g/min) were estimated by using Patlak's method and a two‐compartment model. A corroboration of these results was achieved by using model simulation. In addition, it was possible to generate maps on a pixel‐by‐pixel basis of cerebral perfusion, cerebral blood volume, and blood‐brain barrier permeability. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.     

Quantification of blood flow in brain tumors: comparison of arterial spin labeling and dynamic susceptibility-weighted contrast-enhanced MR imaging

PURPOSE: To implement an arterial spin labeling technique that is feasible in routine examinations and to test the method and compare it with dynamic susceptibility-weighted contrast material-enhanced magnetic resonance (MR) imaging for evaluation of tumor blood flow (TBF) in patients with brain tumors. MATERIALS AND METHODS: Thirty-six patients with histologically proven brain tumors were examined at 1.5 T. A second version of quantitative imaging of perfusion by using a single subtraction with addition of thin-section periodic saturation after inversion and a time delay (Q2TIPS) technique of pulsed arterial spin labeling in the multisection mode was implemented. After arterial spin labeling, a combined T2- and T2*-weighted first-pass bolus perfusion study (gadopentetate dimeglumine, 0.2 mmol/kg) was performed by using a double-echo echo-planar imaging sequence. In regions of interest, maps of absolute and relative cerebral blood flow were computed and analyzed with arterial spin labeling and dynamic susceptibility-weighted contrast-enhanced MR imaging, respectively. RESULTS: Both techniques yielded the highest perfusion values in imaging of glioblastomas and the lowest values in imaging of two low-grade gliomas that both showed strong gadopentetate dimeglumine enhancement. There was a close linear correlation between dynamic susceptibility-weighted contrast-enhanced MR imaging and arterial spin labeling in the tumor region of interest (linear regression coefficient, R = 0.83; P <.005). Blood flow is underestimated with arterial spin labeling at low flow rates. High- and low-grade gliomas can be distinguished at the same level of significance with both methods. Absolute TBF is less important for tumor grading than is the ratio of TBF to age-dependent mean brain perfusion. CONCLUSION: Arterial spin labeling is a suitable method for assessment of microvascular perfusion and allows distinction between high- and low-grade gliomas.     

脑血流灌注显像与灌注加权磁共振成像在脑缺血诊断中的对比研究

目的:通过比较脑血流灌注显像与灌注加权磁共振成像的病变检出率,探讨两种方法在诊断缺血性脑血管病中的价值。方法:将78例缺血性脑血管病患者分为单侧血管病变组和双侧血管病变组,分别对两组患者的两种检查结果进行对比分析。结果:通过比较78例患者两种显像结果发现,脑血流灌注显像及灌注加权磁共振成像的阳性检出率分别为91.03%、76.92%(P=0.016),差异有显著性。单侧血管病变组患者的脑血流灌注显像及PWI的阳性检出率分别为88.37%、79.07%(P=0.243),差异无显著性。双侧血管病变组患者的脑血流灌注显像及PWI的阳性检出率分别为94.29%、74.29%(P=0.022),差异有显著性。结论:在单侧脑血管病变组,脑血流灌注显像与PWI敏感程度相当;而在双侧脑血管病变组,脑血流灌注显像较PWI敏感。