急性卒中的磁共振成像流程探讨

目的：探讨急性卒中发生后影像学诊断的最佳流程。方法：67例发病1～72h的急性卒中患者在CT检查后行T1加权成像（T1 WI）、T2加权成像（T2 WI）、梯度回波T2^＊加权成像（GRE-T2^＊WI）和弥散加权成像（DWI）检查，39例缺血性卒中患者均行灌注加权成像（PWI）检查。结果：28例急性脑出血的出血病灶在GRE-T2^＊WI上全部清楚显影。16例TIA患者T1 WI、T2 WI和GRE-T2^＊WI以及DWI均正常，9例PWI检查灌注降低，7例正常。23例脑梗死患者中，7例发病6h内者GRE-T2^＊WI均正常，6例PWI〉DWI，1例PWI=DWI；16例发病6～72h内的患者GRE-T2^＊WI呈高信号，DWI均可见与体征相对应的高信号病灶，14例PWI=DWI，2例PWI正常。本组14例患者GRE-T2^＊WI像上在基底节区、丘脑、脑干和皮质下发现有1～18个微出血。结论：急性卒中后通过T1 WI、T2 WI、GRE-T2^＊WI、DWI和PWI检查流程可在较短时间内一站式鉴别脑出血、梗死和TIA患者，确定缺血半暗带，帮助溶栓治疗的选择。     

急性脑梗死缺血半暗带演变的磁共振成像研究

目的：探讨应用磁共振弥散／灌注成像技术判断急性脑梗死后缺血半暗带IP存在的范围和时间规律。方法：对72例发病时间在1～24h的急性脑梗死患者行常规MRI、磁共振弥散加权成像（DWI）和磁共振灌注加权成像（PWI）确定IP的范围，计算梗死中心区、IP区及对侧镜像区的ADC值和rADC值并加以比较。结果：26例发病时间〈6h的患者PWI显示存在低灌注区者，其中PWI〉DWI者21例，30例发病时间在6～24h的患者PWI显示存在低灌注区者，其中PWI〉DWI者2例；PWI〉DWI者病灶中心ADC值与IP区及对侧镜像区ADC值差异有统计学意义，其IP区ADC值与其对侧镜像区差异无统计学意义。结论：DWI和PWI结合能灵敏的判断IP的存在，IP存在的时间窗有一定的个体差异。     

急性脑缺血兔磁共振弥散加权成像和灌注加权成像与神经功能缺损的关系

目的研究急性脑缺血兔的弥散加权成像（DWI）及灌注加权成像（PWI）的特点,探讨其与神经功能缺损之间的关系。方法取成年雄性新西兰兔30只,制作大脑中动脉急性脑缺血损伤模型;造模成功后6 h采用Purdy评分评价神经功能损害程度;行MRI DWI和PWI检查,计算DWI高信号区和PWI的脑血流量图（CBF）低灌注区的体积,分析异常信号区体积与神经缺损评分之间的相关性。结果脑缺血兔的CBF低灌注区体积为（91.89±51.31）mm3,DWI高信号区体积为（70.90±43.77）mm3,CBF低灌注区体积大于DWI高信号区,CBF-DWI不匹配区体积为（21.99±16.29）mm3。DWI高信号区和CBF图低灌注区体积均与神经缺损评分呈正相关,CBF-DWI不匹配区体积与神经缺损评分无显著相关性。结论 DWI高信号区与PWI的CBF低灌注区的体积能够反映急性脑缺血兔的神经功能缺损程度。     

磁共振成像技术在缺血性脑血管病临床实践中的意义

目的:评估磁共振成像(MRI)弥散加权成像(DWI)、灌注加权成像(PWI)及磁共振血管造影术(MRA)在缺血性脑血管病临床实践中的意义。方法:对78例发病在10d内的急性缺血性脑血管病患者进行DWI、PWI及MRA检查,对不同发病时期患者的临床与影像改变进行对照研究。结果:急性/亚急性脑梗死灶,相对脑血容量(rCBV)下降,平均通过时间(MTT)延长。62例脑梗死中,41.9％有缺血半暗带,部分患者复查MRI,可发现梗死的进展;58.1％无半暗带存在。急性/亚急性梗死灶DWI表现为高信号,7例患者不同血管分布区有多发新鲜脑梗死灶,陈旧梗死灶表现为低信号。71.8％的患者MBA所显示的血管狭窄或闭塞与DWI病变一致。结论:MBA可提供大的动脉的供血状态;PWI在缺血区提供最早、最直接的血流下降情况;DWI反映脑细胞功能状态。PWI与DWI的研究可确定缺血半暗带,动态观察缺血性损害的进展,判断缺血的预后。     

灌注及弥散磁共振成像在急性缺血性脑卒中的应用

目的　评估磁共振 (MRI)弥散加权成像 (DWI)及灌注加权成像 (PWI)在急性缺血性卒中指导溶栓治疗的应用价值。方法　对 44例急性 (≤ 6h)缺血性卒中患者行DWI、PWI扫描 ,DWI及PWI的不匹配区为缺血半暗带 ,根据半暗带是否存在确定患者是否适合溶栓治疗。结果　脑梗死患者 33例 ,其中 2 3例 (52 3 % )有明显半暗带存在 (PWI >DWI) ;1 0例 (2 2 7% )无明显半暗带 (PWI=DWI)。临床表现为短暂性缺血发作 (TIA)者 1 1例 (2 5 0 % )。结论　PWI及DWI对照研究有助于发现超早期脑梗死半暗带 ,指导溶栓治疗 ;临床表现结合DWI有助于除外TIA     

PWI和DWI对短暂性脑缺血发作的诊断价值

目的观察弥散加权成像（DWI）、灌注加权成像（PWI）对短暂性脑缺血发作（TIA）的诊断价值。方法 34例TIA患者分别行常规头MRI（T1WI、T2WI）、DWI、PWI检查并进行分析。结果全部病例发现9例（26.5%）DWI异常,且T2WI与DWI均显示在同一部位;PWI显示23例（67.6%）异常;PWI异常率明显高于DWI异常（P=0.003）;综合磁共振血管成像（MRA）、数字减影脑血管造影（DSA）及颈动脉超声联合经颅多普勒超声（TCD）（简称超声）检测判定责任血管病变：正常-轻度狭窄21例（61.8%）,中重度狭窄13例（38.2%）。责任血管病变程度与PWI异常差异有统计学意义。结论大部分TIA间期的脑血流灌注异常,部分TIA已经发生脑梗死。应重视TIA的处理以防止TIA复发及脑缺血进展。     

MRI新技术在急性脑梗死诊治中的应用

目的探讨MRI弥散成像(DWI)、灌注成像(PWI)对急性脑梗死的诊断及治疗指导价值。方法发病<24h的急性脑梗死患者79例。立即行MRI常规检查及DWI,16例行PWI检查,14例接受尿激酶溶栓治疗为治疗组,其余65例为对照组。结果DWI对急性脑梗死的诊断率为100%,DWI、T2加权成像(T2WI)、T1加权成像(T1WI)对急性脑梗死诊断准确率为100%、50.6%、36.7%;有显著差异。治疗组治疗前及治疗后72h、3周神经功能缺损程度评分为35.3±3.8、15.7±2.4、12.5±1.6;对照组分别为38.3±3.2、25.7±2.9、19.5±2.6。两组治疗前后神经功能缺损程度评分比较有显著差异。结论DWI对急性脑梗死诊断具有明显优势,DWI与PWI联合应用判断缺血半暗带是否存在,对溶栓治疗有指导作用。超急性期溶栓治疗效果优于其它治疗。     

DWI和PWI在脑梗死中的联合应用价值

目的应用弥散加权成像(DWI)与灌注成像(PWI)在脑梗死中的联合应用,探讨不同时期脑梗死的DWI信号表现特点与血管微循环变化,了解病变与血管微循环之间的关系及判断预后,辅助制定治疗方案。方法选取自2010-04-2011-11收入我院神经内科病房的不同时期脑梗死患者40例,男22例,女18例,除常规序列MRI检查,所有患者均行DWI和PWI检查,用西门子Trio3.0TMR机采集灌注原始数据,在工作站中进行数据后处理,获得MR伪彩灌注图像(包括rCBF图、rCBV图、MTT图、TTP图)进行分析;ADC值的定量测量。结果超急性期脑梗死4例,急性期脑梗死13例,亚急性期脑梗死17例,正常4例,慢性期脑梗死6例,超急性期到慢性期脑梗死DWI信号遵循从高到低,ADC信号遵循从低到高变化特点。DWIPWI 20例DWI=PWI。结论 DWI在超急性脑梗死的诊断中具有重要价值,根据DWI与ADC的信号变化,准确判断脑梗死的各个时期;PWI可以反映梗死区的微血管分布和血流再灌注情况,对脑缺血做出提前诊断,对临床治疗进行指导;DWI与PWI相结合,可以确定缺血半暗带,指导临床治疗     

MR灌注与弥散加权成像不同匹配与急性脑梗死降纤治疗效果的关系

目的 探讨MR灌注加权成像(PWI)与弥散加权成像(DWI)(PWI/DWI)不同匹配与急性脑梗死降纤治疗效果的关系.方法 给38例急性脑梗死患者行巴曲酶降纤治疗,在治疗前予以MR PWI及DWI检查,在治疗前和治疗后进行美国国立卫生研究院卒中量表(NIHSS)评分并评定疗效.比较PWI/DWI不同匹配患者治疗前后的N...     

磁共振弥散加权成像在急性脑梗死诊断中的应用价值研究

目的 研究磁共振弥散加权成像(DWI)诊断急性脑梗死的价值。方法 对86例临床诊断为脑梗死的病例进行DWI和常规MRI扫描,分析在脑梗死不同时期DWI的表现。结果 在起病的超急性期及急性期(>6小时,<48小时)DWI显示率为100％,病灶大小为(24.8±21.6)mm,T2/FLAIR上病灶大小为(7.9±6.8)mm,两者比较的t=12.7,P<0.05,在亚急性期(2～14天)DWI与T2W加Flair比较,DWI不如T2W加Flair,对于慢性期脑梗死(超过14天),DWI不易辨认。结论DWI对急性期脑梗死的诊断准确率高,明显优于常规MRI。     

Diffusion-weighted and perfusion-weighted magnetic resonance imaging to monitor acute intra-arterial thrombolysis

Diffusion-weighted and perfusion-weighted magnetic resonance imaging (DWI, PWI) are useful in detecting early cerebral ischemic lesions. Intra-arterial thrombolysis is an effective treatment for some patients with acute thromboembolic occlusion. We evaluated the efficacy of acute thrombolytic therapy by using DWI and PWI in 3 patients who presented with internal carotid artery or middle cerebral artery occlusion. On the initial magnetic resonance imaging scans, the abnormal areas shown by PWI were bigger than those shown by DWI. All patients received thrombolytic therapy within 6 hours after stroke onset. In 1 patient, the hyperintensity area detected by initial DWI scanning diminished after thrombolysis. DWI and PWI may be useful to monitor the effectiveness of intra-arterial thrombolysis.     

核磁共振脑灌注成像及DWI联合应用在诊断早期脑梗死缺血半暗带中的临床价值

目的 探讨核磁共振脑部灌注加权成像(PWI)及脑部弥散加权成像(DWI)联合应用在诊断早期脑梗死缺血半暗带中的临床价值。方法 本研究中的受试对象均来自2016年1月-2017年4月来本院就诊的脑梗死患者,选出符合纳入标准的100例作为研究对象,并根据脑梗死发生时间分成超急性期、急性期、亚急性期和慢性期,分别观察PWI和DWI表现,以表观弥散系数(ADC)为DWI的检测评价指标,以局部脑血容量(rCBV)、局部脑血流量(rCBF)、平均通过时间(MTT)和达峰时间(TTP)为PWI的检测评价指标,并比较不同时期脑梗死的PWI和DWI表现。结果 随着脑梗死患者发病时间的延长,T₂WI显示信号随之增高,DWI信号随之降低,ADC信号随之增高。随着梗死时间延长,梗死区ADC值随之增加,健侧对应区随着梗死时间的变化,ADC值无明显变化; 在每个不同分期中健侧对应区的ADC值均高于梗死区(P均<0.05); 超急性期rCBV和rCBF值均为降低信号,MTT和TTP均为升高信号; 急性期rCBV、rCBF、MTT和TTP值在三种信号上均有表现,但rCBV和rCBF值均以降低信号为主,MTT和TTP均以升高信号为主; 亚急性期中rCBV和rCBF为正常和降低信号,其中以正常信号为主,MTT和TTP均为降低和升高信号,并以升高信号为主; 慢性期rCBV和rCBF均表现为降低信号,MTT和TTP均为降低和升高信号,并以降低信号为主; 超急性期DWIPWI均有表现,并以DWIPWI均有表现,并以DWIPWI为主; 亚急性期DWI=PWI和DWI>PWI均有表现,并以DWI=PWI为主; 慢性期均为DWI=PWI。结论 PWI联合DWI对脑梗死早期的诊断价值较高,PWI对缺血半暗带有较好的诊断,其与DWI相结合可更准确地判定缺血半暗带。     

Diffusion- and perfusion-weighted MRI. The DWI/PWI mismatch region in acute stroke.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) are relatively new MR techniques increasingly used in acute stroke. During the first hours of stroke evolution, the regions with abnormal perfusion are typically larger than the DWI lesions, and this mismatch region has been suggested to be "tissue at risk." The aim of this study was to evaluate the PWI/DWI mismatch region in acute stroke patients and find parameters indicative of both infarct progression and functional impairment. METHODS: Twenty patients with nonlacunar ischemic stroke were imaged with DWI, PWI, and conventional MRI within 24 hours of symptom onset and after 1 week; in addition, the European Stroke Scale (ESS) score was recorded. With PWI, the volumes of regions with "time-to-peak" (TTP) delays of >/=2, 4, 6, 8, and 10 seconds were measured; these volumes were compared with the acute DWI lesion volumes, final infarct size, and ESS score. RESULTS: In 80% of patients the acute DWI lesion was surrounded by regions with abnormal TTP delays (PWI>DWI lesion). A TTP delay of >/=6 s in the mismatch region was found to be associated with lesion enlargement between the initial and follow-up MRI scans. Lesions increased in 9 of 12 patients (75%) in whom the area with TTP delay >/=6 s was larger than the DWI lesion, but they increased in only 1 of 8 (12.5%) of the remaining patients, in whom the area with a TTP delay >/=6 s was smaller than the DWI lesion. The volume of the regions with TTP delays of >/=4 s correlated better with ESS (r=-0.88, P<0.001) than other PWI (or DWI) volumes, which indicated that a TTP delay of approximately 4 s might be the threshold for functional impairment of brain tissue. CONCLUSIONS: Only patients with severe perfusion deficits in the PWI/DWI mismatch (TTP delays of >/=6 s) are at high risk of lesion enlargement. Functionally, more moderate perfusion deficits (TTP delays >/=4 and <6 s) appear to also contribute to the acute clinical deficit.     

Detection of the ischemic penumbra using pH-weighted MRI.

The classic definition of the ischemic penumbra is a hypoperfused region in which metabolism is impaired, but still sufficient to maintain cellular polarization. Perfusion- and diffusion-weighted MRI (PWI, DWI) can identify regions of reduced perfusion and cellular depolarization, respectively, but it often remains unclear whether a PWI-DWI mismatch corresponds to benign oligemia or a true penumbra. We hypothesized that pH-weighted MRI (pHWI) can subdivide the PWI-DWI mismatch into these regions. Twenty-one rats underwent permanent middle cerebral artery occlusion and ischemic evolution over the first 3.5 h post-occlusion was studied using multiparametric MRI. End point was the stroke area defined by T(2)-hyperintensity at 24 h. In the acute phase, areas of reduced pH were always larger than or equal to DWI deficits and smaller than or equal to PWI deficits. Group analysis showed that pHWI deficits during this phase coincided with the resulting infarct area at endpoint. Final infarcts were smaller than PWI deficits (range 65% to 90%, depending on the severity of the occlusion) and much larger than acute DWI deficits. These data suggest that the outer boundary of the hypoperfused area showing a decrease in pH without DWI abnormality may correspond to the outer boundary of the ischemic penumbra, while the hypoperfused region at normal pH may correspond to benign oligemia. These first results show that pHWI can provide information complementary to PWI and DWI in the delineation of ischemic tissue.     

Intra-arterial rtPA treatment of stroke assessed by diffusion- and perfusion-weighted MRI

BACKGROUND: Diffusion-weighted MRI (DWI) and perfusion-weighted MRI (PWI) are new techniques that can be used for the evaluation of acute ischemic stroke. However, their potential role in the management of patients treated with recombinant tissue plasminogen activator (rtPA) has yet to be determined. CASE DESCRIPTION: The authors present the case of a 73-year-old man who was treated with intra-arterial rtPA, and they compare findings on DWI and PWI scans with angiography. PWI revealed decreased cerebral perfusion corresponding to an area that was not successfully recanalized, but revealed no abnormality in regions in which blood flow was restored. DWI was unremarkable in the region that was reperfused early (3 hours) but revealed hyperintensity in an area that was reperfused 3. 5 hours after symptom onset and in the area that was not reperfused. CONCLUSIONS: Findings on PWI correlated well with angiography, and DWI detected injured tissue in the hyperacute stage, whereas conventional MRI findings were negative. This suggests that these techniques may be useful to noninvasively evaluate the success of thrombolytic therapy.     

Feasibility of establishing cerebral ischemia models by using aerocyst-blocking bilateral ascending pharyngeal artery of piglets Imaging assessment

BACKGROUND: The cerebral ischemia and ischemia/reperfusion animal models are used to simulate the human cerebrovascular diseases is one of the popular topics of neurological science recently. To study the pathophysiology, pathogenesis, prophylaxis and treatment of ischemic cerebrovascular diseases and to establish the ideal animal model that is the most similar to the human cerebral ischemia, are the topics that the people generally cared about. OBJECTIVE: To evaluate the effects of aerocyst-blocking bilateral ascending pharyngeal artery on the establishment of cerebral ischemia models by using digital subtraction angiography (DSA), magnetic resonance diffusion-weighted imaging (DWI) and magnetic resonance perfusion-weighted imaging (PWI). DESIGN: Repetitive measure animal experiment. SETTING: Zhongshan Hospital Affiliated to Dalian University. MATERIALS: The experiment was carried out in the Animal Laboratory (Provincial Laboratory), Zhongshan Hospital of Dalian Univeristy from January to May 2006. A total of 14 domestic piglets, of 6 months old, weighing 12–15 kg, of either gender, were selected from Animal Experimental Center, Dalian University. Multistar T.O.P digital subtraction angiography machine was provided by Siemens Company, German. METHODS: Aerocyst-blocking bilateral ascending pharyngeal artery was used to establish cerebral ischemia models. And then, Multistar T.O.P. DSA was used for imaging of cerebral vessels before blocking, during blocking and at 0.5 and 2 hours after ischemia perfusion. GE Signa 1.5 T supraconduction magnetic resonance imaging was used for DWI examination; in addition, PWI was used based on focal sites and areas. Otherwise, magnetic resonance imaging (MRI) was used to detect signal changes of T1WI and T2WI in ischemic areas. MAIN OUTCOME MEASURES: Analytic results of DSA, DWI, PWI and MRI. RESULTS: All 14 experimental piglets were involved in the final analysis. ① DSA: The blood flow of bilateral ascending pharyngeal arteries and its branch were blocked at blocking phase, which restored 0.5 and 2 hours after reperfusion. ② DWI and PWI: There were no observable abnormalities in PWI and DWI at pre-blocking. Abnormal increased signals were found on both DWI and PWI at during and post-blocking. There were reduction in ADC and rCBF and delay in rTTP at all time points except pre-blocking. ③ MRI: There were no abnormal signals observable at any time of pre- and post-blocking in T1WI and T2WI. CONCLUSION: It is feasible to establish this kind of animal experimental models, and it can simulate the ischemic state; meanwhile, the existence and extent can be showed directly by DSA, DWI, and PWI.     

Prediction of hemorrhagic transformation following acute stroke: role of diffusion- and perfusion-weighted magnetic resonance imaging

BACKGROUND: Acute diffusion-weighted (DWI) and perfusion-weighted (PWI) magnetic resonance imaging (MRI) findings may correlate with secondary hemorrhagic transformation (HT) risk in patients with stroke. This information could be of value, particularly in individuals being considered for thrombolytic therapy. OBJECTIVE: To determine the relationship between DWI and PWI findings and the risk of secondary HT in patients with acute stroke. DESIGN: Retrospective case series. SETTING: Academic medical center. PATIENTS: Twenty-seven patients with acute stroke capable of being evaluated with DWI/PWI 8 hours or less after symptom onset. MAIN OUTCOME MEASURES: Apparent diffusion coefficient values, perfusion delay measurements, and subsequent MRI or computed tomographic scans detected HT. RESULTS: The mean +/- SD apparent diffusion coefficient of ischemic regions that experienced HT was significantly lower than the overall mean +/- SD apparent diffusion coefficient of all ischemic areas analyzed (0.510 +/- 0.140 x 10(-3) mm(2)/s vs 623 +/- 0.113 x 10(-3) mm(2)/s; P =.004). This difference remained significant when comparing the HT-destined ischemic areas with the non-HT-destined areas within the same ischemic lesion (P =.02). Patients receiving recombinant tissue-type plasminogen activator (rt-PA) experienced HT significantly earlier than patients not receiving rt-PA (P =.002). Moreover, a persistent perfusion deficit in the area of subsequent hemorrhage at 3 to 6 hours after the initial MRI scan was identified in significantly more patients who experienced HT than in those who did not (83% vs 30%; P =.03). CONCLUSION: Both DWI and PWI scans detect abnormalities that are associated with HT. These findings support a role for MRI in identifying patients who are at increased risk for secondary HT following acute ischemic stroke.     

Relationship between severity of MR perfusion deficit and DWI lesion evolution

OBJECTIVE: To assess whether a quantitative analysis of the severity of the early perfusion deficit on MRI in acute ischemic stroke predicts the evolution of the perfusion/diffusion mismatch and to determine thresholds of hypoperfusion that can distinguish between critical and noncritical hypoperfusion. METHODS: Patients with acute ischemic stroke were studied in whom perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI MRI) were performed within 7 hours of symptom onset and again after 4 to 7 days. Patients with early important decreases in points on the NIH Stroke Scale were excluded. Maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) were created. These hemodynamic parameters were correlated with the degree of recruitment of the baseline PWI lesion by the DWI lesion. RESULTS: Twelve patients had an initial PWI > DWI mismatch of >20%. A linear relationship was observed between the initial MTT and the degree of recruitment of the baseline PWI lesion by the DWI lesion at follow-up (R(2) = 0.9, p < 0.001). Higher CBV values were associated with higher degrees of recruitment (rho = 0.732, p < 0.007). The volume of MTT of >4 (R(2) = 0.86, p < 0.001) or >6 seconds (R(2) = 0.85, p < 0.001) predicted final infarct size. CONCLUSION: Among patients who have had an acute stroke with PWI > DWI, who do not have dramatic early clinical improvement, the degree of expansion of the initial DWI lesion correlates with the severity of the initial perfusion deficit as measured by the mean transit time and the cerebral blood volume.     

Combined diffusion and perfusion MRI with correlation to single-photon emission CT in acute ischemic stroke. Ischemic penumbra predicts infarct growth.

BACKGROUND AND PURPOSE: More effective imaging methods are needed to overcome the limitations of CT in the investigation of treatments for acute ischemic stroke. Diffusion-weighted MRI (DWI) is sensitive in detecting infarcted brain tissue, whereas perfusion-weighted MRI (PWI) can detect brain perfusion in the same imaging session. Combining these methods may help in identifying the ischemic penumbra, which is an important concept in the hemodynamics of acute stroke. The purpose of this study was to determine whether combined DWI and PWI in acute (<24 hours) ischemic stroke can predict infarct growth and final size. METHODS: Forty-six patients with acute ischemic stroke underwent DWI and PWI on days 1, 2, and 8. No patient received thrombolysis. Twenty-three patients underwent single-photon emission CT in the acute phase. Lesion volumes were measured from DWI, SPECT, and maps of relative cerebral blood flow calculated from PWI. RESULTS: The mean volume of infarcted tissue detected by DWI increased from 46.1 to 75.6 cm(3) between days 1 and 2 (P<0.001; n=46) and to 78.5 cm(3) after 1 week (P<0.001; n=42). The perfusion-diffusion mismatch correlated with infarct growth (r=0. 699, P<0.001). The volume of hypoperfusion on the initial PWI correlated with final infarct size (r=0.827, P<0.001). The hypoperfusion volumes detected by PWI and SPECT correlated significantly (r=0.824, P<0.001). CONCLUSIONS: Combined DWI and PWI can predict infarct enlargement in acute stroke. PWI can detect hypoperfused brain tissue in good agreement with SPECT in acute stroke.     

Correlation between diffusion- and perfusion-weighted MRI and neurological deficit measured by the Scandinavian Stroke Scale and Barthel Index in hyperacute subcortical stroke (< or = 6 hours)

OBJECTIVE: We used combined diffusion-weighted (DWI) and perfusion-weighted (PWI) MRI to characterize hyperacute infarctions within 6 h of symptom onset with special reference to subcortical infarctions, and investigated the relation between perfusion-diffusion mismatch volume and functional outcome. MATERIAL AND METHODS: Twenty-two patients presenting with symptoms of acute stroke underwent DWI and PWI within 6 h of symptom onset, and follow-up MRI 30 days later. Twelve of these had a subcortical infarction on acute DWI. Lesion volumes were measured by acute DWI and PWI as well as chronic T(2)-weighted MRI (T2WI). Clinical severity was measured by the Scandinavian Stroke Scale (SSS) and the Barthel Index (BI). RESULTS: In the 12 patients with subcortical infarctions, PWI and especially DWI correlated strongly with acute and chronic neurological SSS score, as well as with final infarct volume. Furthermore, a hyperacute PWI/DWI mismatch in this subgroup predicted lesion growth. There was a weaker correlation between acute DWI/PWI and neurological score among all 22 patients, and patients with a PWI/DWI mismatch larger than 100 ml had a significantly larger lesion growth and a poorer outcome than patients with a smaller mismatch. CONCLUSIONS: Subcortical infarctions may represent a sizeable subgroup of acute stroke patients. Also subcortical infarctions may have a PWI/DWI mismatch and therefore may respond to neuroprotective/thrombolytic therapy. Hyperacute DWI may reflect the acute clinical status and predict the outcome in patients with subcortical infarction.