磁共振灌注成像－弥散成像不匹配对指导超时间窗急性缺血性卒中患者溶栓的价值

目的 探讨磁共振灌注成像－弥散成像（perfusion weighted imaging-diffusion weighted imaging,PWI-DWI）不匹配对指导超时间窗（>6h）的急性缺血性卒中患者溶栓的价值。方法 选择在发病12h内完成磁共振检查,且（PWI-DWI）/DWI×100%>30%的40例急性缺血性卒中患者,分为溶栓组和对照组,溶栓组给予重组组织型纤溶酶原激活剂（recombinant tissue plasminogen activator,rt-PA）0.6～0.9mg/kg静脉溶栓治疗,对照组常规治疗。两组患者在溶栓前、溶栓后1周、2周、3个月分别行美国国立卫生院卒中量表（National Institutes of Health Stroke Scale,NIHSS）评分,溶栓前、溶栓后2周、3个月分别行日常生活能力量表（activities of daily living,ADL）评分。结果 溶栓组在溶栓后1周、2周、3个月NIHSS评分均较对照组降低（P<0.01）;在2周和3个月,溶栓组ADL评分较对照组明显升高（P<0.01）。结论 在PWI>DWI影像学模式指导下,适当延长急性缺血性卒中的溶栓时间窗具有可行性。     

Influence of pretreatment MRI parameters on clinical outcome, recanalization and infarct size in 49 stroke patients treated by intravenous tissue plasminogen activator

We hypothesized that pretreatment magnetic resonance imaging (MRI) parameters might predict clinical outcome, recanalization and final infarct size in acute ischemic stroke patients treated by intravenous recombinant tissue plasminogen activator (rt-PA). MRI was performed prior to thrombolysis and at day 1 with the following sequences: magnetic resonance angiography (MRA), T2*-gradient echo (GE) imaging, diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI). Final infarct size was assessed at day 60 by T2-weighted imaging (T2-WI). The National Institutes of Health Stroke Scale (NIHSS) score was assessed prior to rt-PA therapy and the modified Rankin Scale (m-RS) score was assessed at day 60. A poor outcome was defined as a day 60 m-RS score >2. Univariate and multivariate logistic regression analyses were used to identify the predictors of clinical outcome, recanalization and infarct size. Forty-nine patients fulfilled the inclusion criteria. Baseline NIHSS score was the best independent indicator of clinical outcome (p=0.002). A worse clinical outcome was observed in patients with tandem internal carotid artery (ICA)+middle cerebral artery (MCA) occlusion versus other sites of arterial occlusion (p=0.009), and in patients with larger pretreatment PWI (p=0.001) and DWI (p=0.01) lesion volumes. Two factors predict a low rate of recanalization: a proximal site of arterial occlusion (p=0.02) and a delayed time to peak (TTP) on pretreatment PWI (p=0.05). The final infarct size was correlated with pretreatment DWI lesion volume (p=0.025). Recanalization was associated with a lower final infarct size (p=0.003). In conclusion, a severe baseline NIHSS score, a critical level of pretreatment DWI/PWI parameters and a proximal site of occlusion are predictive of a worse outcome after IV rt-PA for acute ischemic stroke.     

磁共振弥散加权成像在急性脑梗死动脉溶栓治疗中的应用

目的观察磁共振弥散加权成像(DWI)在大脑中动脉供血区脑梗死动脉溶栓治疗前后变化的临床意义。方法对20例发病小于6h的大脑中动脉供血区脑梗死患者,采用MRA-DWI不匹配方法判断存在半暗带后,行选择动脉尿激酶溶栓治疗。所有再通病例均于1w至10d内复查MR,注意观察对比DWI的变化。结果血管再通患者1w¹0d内复查MR,DWI高信号区域明显缩小。结论急性脑梗死DWI动态观察是动脉溶栓治疗一个临床观测指标。     

Thrombolytic reversal of acute human cerebral ischemic injury shown by diffusion/perfusion magnetic resonance imaging

Diffusion magnetic resonance imaging provides an early marker of acute cerebral ischemic injury. Thrombolytic reversal of diffusion abnormalities has not previously been demonstrated in humans. Serial diffusion and perfusion imaging studies were acquired in patients experiencing acute hemispheric cerebral ischemia treated with intra-arterial thrombolytic therapy within 6 hours of symptom onset. Seven patients met inclusion criteria of prethrombolysis and postthrombolysis magnetic resonance studies, presence of large artery anterior circulation occlusion at angiography, and achievement of vessel recanalization. Mean diffusion-weighted imaging lesion volume at baseline was 23 cm3 (95% confidence interval [95% CI], 8-38 cm3) and decreased to 10 cm3 (95% CI, 3-17 cm3) 2.5 to 9.5 hours after thrombolysis. Mean apparent diffusion coefficient lesion volume decreased from 9 cm3 (95% CI, 2-16 cm3) at baseline to 1 cm3 (95% CI, 0.4-2 cm3) early after thrombolysis. A secondary increase in diffusion volumes was seen in 3 of 6 patients at day 7. In all 4 patients in whom perfusion imaging was obtained before and after treatment, complete resolution of the perfusion deficit was shown. Diffusion magnetic resonance signatures of early tissue ischemic injury can be reversed in humans by prompt thrombolytic vessel recanalization. The ischemic penumbra includes not only the region of diffusion/perfusion mismatch, but also portions of the region of initial diffusion abnormality.     

Delayed intravenous thrombolysis based on MRI mismatch in posterior circulation stroke

The current time-based approach for patient selection for intravenous (IV) thrombolysis in an acute stroke setting neglects the individual variation of cerebral blood flow impairment. This approach restricts the eligible patient population. In the last decade, advanced imaging and especially MRI diffusion- and perfusion-weighted imaging (DWI–PWI) techniques have been used to select patients for IV thrombolysis outside the current 4.5 h time window. Most of these studies focus on the anterior (carotid artery) cerebral circulation only. We report the case of an acute ischemic stroke due to a dissection of the right vertebral artery and occlusion of the posterior inferior cerebellar artery with good clinical outcome. The patient received IV thrombolysis far beyond the current established time window. This decision was based upon a marked MRI DWI–PWI mismatch zone in the posterior circulation territory.     

Seizure at stroke onset: should it be an absolute contraindication to thrombolysis?

BACKGROUND: Current guidelines for the treatment of acute ischemic stroke exclude patients with seizure at stroke onset from consideration for thrombolytic therapy. It may be difficult to differentiate an ischemic stroke from postictal Todd's paralysis by clinical examination and noncontrast CT scan. Magnetic resonance imaging (MRI) with diffusion- (DWI) and perfusion-weighted images (PWI) and angiography (MRA) can be used to confirm the diagnosis of an acute ischemic process in the presence of concurrent seizures. METHODS: A case report of a patient who presented with seizures, in whom the combination of DWI/PWI MRI and MRA confirmed the diagnosis of an embolic ischemic stroke. The patient was treated with intravenous recombinant tissue plasminogen activator with clinical and radiological improvement. CONCLUSIONS: Treatment decisions with regard to thrombolysis in acute stroke patients should be based on parameters of cerebral perfusion, assessment of collateral blood flow and presence of potentially salvageable tissue. Modern neuroimaging techniques that can rapidly assess these variables, such as DWI/PWI MRI and MRA, can improve the current selection of patients who are likely to benefit from thrombolysis and extend its benefit to patients who would otherwise be excluded, such as those with seizures at stroke onset.     

Advances in penumbra imaging with MR

The concept of the ischaemic penumbra as critically hypoperfused and functionally impaired, but potentially viable brain, was introduced over 25 years ago. Recent studies have used a combination of perfusion-weighted magnetic resonance imaging (PWI) and diffusion-weighted imaging (DWI) to delineate the putative penumbra. PWI provides semiquantitative cerebral blood flow imaging and DWI is an index of the largely irreversible ischaemic core. PWI > DWI mismatch is an operational definition of the penumbra that was introduced in the late 1990s. This definition has been modified in recent years with the recognition that the PWI boundary includes a region of benign oligaemia and that a portion of the DWI core is potentially salvageable with rapid reperfusion. An MRI penumbral signature is present in the majority of patients within 6 h of stroke onset, often but not invariably associated with proximal arterial occlusion on magnetic resonance angiography, and is strictly time dependent. It has been postulated that penumbral imaging using MRI can provide a physiological 'tissue clock' and be used to predict benefit from thrombolytic therapy beyond the established 3-hour window. This has been suggested by pilot studies, but confirmation will rely on ongoing, prospective, randomized trials. The presence and extent of the penumbra may also predict the opportunity for tissue salvage with neuroprotection strategies. DWI and PWI parameters are being used in proof-of-principle stroke trials. Such trials can be performed with 100-200 patients randomized between treated and control groups and provide a biological signal of efficacy with only 10% of the sample size required for a Phase III study.     

颅脑静脉窦内血栓磁共振弥散加权成像对溶栓治疗的价值

目的 探讨颅脑静脉窦内血栓磁共振弥散加权成像(DWl)的特征以及DWI表现与溶栓治疗后血管再通的关系.方法 回顾性分析14例颅脑静脉窦内血栓患者的MRI表现,包括常规MRJ、FLAIR、DWI及MRV,统计静脉窦内出现DWI高信号的部位、数量;以溶栓治疗后1～3个月的MRV确定原栓塞静脉窦是否再通;探讨溶栓前静脉窦内血栓T1WI、FLAIR、DWI表现与溶栓治疗后血管再通的关系.结果 14例颅脑静脉窦内血栓患者中9例出现21个部位的血栓DWI高信号.首诊MRI血栓内有DWI高信号的静脉窦的血管完全再通的几率较低(19.0%),血栓内无DWI高信号的静脉窦冉通率较高(68.2%),比较差异有统计学意义(P=0.005).结论 颅脑静脉窦内血栓患者血栓DWI信号可能与血栓的进展有关,首诊MRI发现静脉窦内血栓DWI呈高信号能预测溶栓治疗1～3个月后血管再通率较低.     

Early magnetic resonance imaging prediction of arterial recanalization and late infarct volume in acute carotid artery stroke.

In patients with acute ischemic stroke, early recanalization may save tissue at risk for ischemic infarction, thus resulting in smaller infarcts and better clinical outcome. The hypothesis that clinical and diffusion- and perfusion-weighted imaging (DWI, PWI) parameters may have a predictive value for early recanalization and final infarct size was assessed. Twenty-nine patients were prospectively enrolled and underwent sequential magnetic resonance imaging (1) within 6 hours from hemispheric stroke onset, before thrombolytic therapy; (2) at day 1; and (3) at day 60. Late infarct volume was assessed by T2 -weighted imaging. At each time, clinical status was assessed by the National Institutes of Health Stroke Scale (NIHSS). Twenty-eight patients had arterial occlusion at day 0 magnetic resonance angiography (MRA). They were classified into two groups according to day 1 MRA: recanalization (n = 18) versus persistent occlusion (n = 10). Any significant differences between these groups were assessed regarding (1) PWI and DWI abnormality volumes, (2) relative and absolute time-to-peak (TTP) and apparent diffusion coefficient within the lesion on DWI; and (3) day 60 lesion volume on T2 -weighted imaging. Univariate and multivariate logistic regression analysis showed that the most powerful predictive factors for recanalization were lower baseline NIHSS score and lower baseline absolute TTP within the lesion on DWI. The best predictors of late infarct size were day 0 lesion volume on DWI and day 1 recanalization. Early PWI and DWI studies and day 1 MRA provide relevant predictive information on stroke outcome.     

Monitoring intravenous recombinant tissue plasminogen activator thrombolysis for acute ischemic stroke with diffusion and perfusion MRI

BACKGROUND AND PURPOSE: Intravenous recombinant tissue plasminogen activator (rtPA) administration is an effective therapy for ischemic stroke when initiated within 3 hours and possibly up to 6 hours after symptom onset. To improve patient selection, a fast diagnostic tool that allows reliable diagnosis of hemorrhage and ischemia, vessel status, and tissue at risk at an early stage may be useful. We studied the feasibility of stroke MRI for the initial evaluation and follow-up monitoring of patients undergoing intravenous thrombolysis. METHODS: Stroke MRI (diffusion- and perfusion-weighted imaging [DWI and PWI, respectively], magnetic resonance angiography, and T2-weighted imaging) was performed before, during, or after thrombolysis and on days 2 and 5. We assessed clinical scores (National Institutes of Health Stroke Scale [NIHSS], Scandinavian Stroke Scale [SSS], Barthel Index, and Rankin scale) at days 1, 2, 5, 30, and 90. Furthermore, we performed volumetric analysis of infarct volumes on days 1, 2, and 5 as shown in PWI, DWI, and T2-weighted imaging. RESULTS: Twenty-four patients received rtPA within a mean time interval after symptom onset of 3.27 hours and stroke MRI of 3.43 hours. Vessel occlusion was present in 20 of 24 patients; 11 vessels recanalized (group 1), and 9 did not (group 2). The baseline PWI lesion volume was significantly larger (P=0.008) than outcome lesion size in group 1, whereas baseline DWI lesion volume was significantly smaller (P=0.008) than final infarct size in group 2. Intergroup outcome differed significantly for all scores at days 30 and 90 (all P<0.01). Intragroup differences were significant in group 1 for change in SSS and NIHSS between day 1 and day 30 (P=0.003) and for SSS only between day 1 and day 90 (P=0.004). CONCLUSIONS: Stroke MRI provides comprehensive prognostically relevant information regarding the brain in hyperacute stroke. Stroke MRI may be used as a single imaging tool in acute stroke to identify and monitor candidates for thrombolysis. It is proposed that stroke MRI is safe, reliable, and cost effective; however, our data do not prove this assumption. Early recanalization achieved by thrombolysis can save tissue at risk if present and may result in significantly smaller infarcts and a significantly better outcome.     

Early motor evoked potentials in acute stroke: adjunctive measure to MRI for assessment of prognosis in acute stroke within 6 hours

BACKGROUND: In acute stroke, a magnetic resonance (MR) perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) mismatch (PWI>DWI mismatch) may indicate tissue at risk for infarction and poor prognosis. However, different to early enthusiasm about this surrogate marker, its validity has shown several drawbacks in individual patients. Rather than relying on imaging, we evaluated motor evoked potentials (MEP) as a measure of cerebral function in the acute stroke setting. METHODS: Thirteen patients with acute hemiparetic stroke underwent time to peak PWI and DWI within 6 h after onset as well as recordings of early MEP of first dorsal interosseous muscles. Outcome was assessed by the Unified Neurological Stroke Scale and Barthel Index at day 42. RESULTS: Of 8 patients with PWI>DWI mismatch, 4 patients with normal MEP had a good clinical outcome and 4 patients with absent or pathological MEP had an unfavourable outcome (p < 0.05, Fisher's exact test). In all patients without PWI>DWI mismatch, MEP findings predicted clinical outcome. Normal MEP at day 0--but not PWI/DWI findings--significantly correlated with a good clinical outcome. CONCLUSIONS: Early MEP recordings in acute stroke patients provide valid prognostic information; they may become more useful for specific treatment decisions than presently available MRI surrogate parameters.     

Lesion development and reperfusion benefit in relation to vascular occlusion patterns after embolic stroke in rats

Vascular occlusion sites largely determine the pattern of cerebral tissue damage and likelihood of subsequent reperfusion after acute ischemic stroke. We aimed to elucidate relationships between flow obstruction in segments of the internal carotid artery (ICA) and middle cerebral artery (MCA), and (1) profiles of acute ischemic lesions and (2) probability of subsequent beneficial reperfusion. Embolic stroke was induced by unilateral intracarotid blood clot injection in normotensive (n=53) or spontaneously hypertensive (n=20) rats, followed within 2 hours by magnetic resonance (MR) angiography (MRA), diffusion- (DWI) and perfusion-weighted magnetic resonance imaging (MRI) (PWI). In a subset of animals (n=9), MRI was repeated after 24 and 168 hours to determine the predictive value of the occlusion pattern on benefit of reperfusion. The extent of cerebral perfusion and diffusion abnormality was related to the pattern of flow obstruction in ICA and MCA segments. Hypertensive animals displayed significantly larger cortical perfusion lesions. Acute perfusion-diffusion lesion mismatches were detected in all animals that subsequently benefitted from reperfusion. Yet, the presence of an angiography-diffusion mismatch was more specific in predicting reperfusion benefit. Combination of DWI, PWI, and MRA exclusively informs on the impact of arterial occlusion profiles after acute ischemic stroke, which may improve prognostication and subsequent treatment decisions.     

Expanding the window for thrombolytic therapy in acute stroke. The potential role of acute MRI for patient selection.

BACKGROUND: Effective therapy was not available for treatment of acute stroke until 1995, when tissue plasminogen activator (tPA) was shown to improve neurological and functional outcome in stroke patients who were treated within 3 hours of symptom onset. SUMMARY OF REVIEW: Currently, many patients do not qualify for tPA therapy because they present for evaluation beyond 3 hours after stroke onset. Attempts to expand the treatment window to 6 hours, using CT to select patients, have failed. Use of early MR imaging may provide significant advantages over CT for identification of patients who are likely to benefit from thrombolytic therapy because (1) the early perfusion-weighted imaging (PWI) lesion estimates the region of acute dysfunctional brain tissue, whereas the acute diffusion-weighted imaging (DWI) lesion appears to correspond to the core of the early infarction; (2) the mismatch between the acute PWI lesion and the smaller DWI lesion represents potentially salvageable brain tissue (an estimate of the ischemic penumbra); and (3) in patients with a PWI/DWI mismatch, early reperfusion is often associated with substantial clinical improvement and reversal or reduction of DWI lesion growth. CONCLUSIONS: Clinical trials that use new MRI techniques to screen patients may be able to identify a subset of acute stroke patients who are ideal candidates for thrombolytic therapy even beyond 3 hours after stroke onset.     

Stroke magnetic resonance imaging within 6 hours after onset of hyperacute cerebral ischemia

We studied the diagnostic and prognostic value of diffusion- and perfusion-weighted magnetic resonancce imaging (DWI and PWI) for the initial evaluation and follow-up monitoring of patients with stroke that had ensued less than 6 hours previously. Further, we examined the role of vessel patency or occlusion and subsequent recanalization or persistent occlusion for further clinical and morphological stroke progression so as to define categories of patients and facilitate treatment decisions. Fifty-one patients underwent stroke magnetic resonance imaging (DWI, PWI, magnetic resonance angiography, and T2-weighted imaging) within 3.3 +/- 1.29 hours, and, of those, 41 underwent follow-up magnetic resonance imaging on day 2 and 28 on day 5. In addition, we assessed clinical scores (on the National Institutes of Health Stroke Scale, Scandinavian Stroke Scale, Barthel Index, and Modified Rankin Scale) on days 1, 2, 5, 30, and 90 and performed volumetric analysis of lesion volumes. In all, 25 patients had a proximal, 18 a distal, and 8 no vessel occlusion. Furthermore, 15 of 43 patients exhibited recanalization on day 2. Vessel occlusion was associated with a PWI-DWI mismatch on the initial magnetic resonance imaging, vessel patency with a PWI-DWI match (p < 0.0001). Outcome scores and lesion volumes differed significantly between patients experiencing recanalization and those who did not (all p < 0.0001). Acute DWI and PWI lesion volumes correlated poorly with acute clinical scores and only modestly with outcome scores. We have concluded on the basis of this study that early recanalization saves tissue at risk of ischemic infarction and results in significantly smaller infarcts and a significantly better clinical outcome. Patients with proximal vessel occlusions have a larger amount of tissue at risk, a lower recanalization rate, and a worse outcome. Urgent recanalization seems to be of utmost importance for these patients.     

Multimodality MRI and MRA for Decision Making in Minor Stroke: A Case with Internal Carotid and Distal Middle Cerebral Artery Occlusion

We report the case of a 65‐year‐old man who presented with mild, rapidly improving stroke symptoms. Acute magnetic resonance imaging disclosed no diffusion abnormalities but a tandem internal carotid artery/distal middle cerebral artery occlusion associated with a large corresponding deficit on perfusion imaging. In addition, there was a cross‐flow to the middle cerebral artery via the anterior communicating artery. Therefore, intravenous thrombolysis was initiated that led to rapid reopening of the middle cerebral artery and left the patient free of symptoms. Our observation highlights the possible benefit of systemic thrombolytic treatment even in the setting of an internal carotid artery occlusion and the substantial contribution of multimodal magnetic resonance imaging for a risk‐benefit estimate.     

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.     

Magnetic resonance imaging in basilar artery occlusion

CONTEXT: Acute basilar artery occlusion has particularly high mortality and morbidity. OBJECTIVE: To determine the potential utility of advanced magnetic resonance imaging (MRI) methods, including diffusion-weighted imaging, for the early management of patients with basilar artery thrombosis. DESIGN: Case series. SETTING: Institute of Neuroradiology and Department of Neurology, Johann Wolfgang Goethe University, Frankfurt, Germany. PATIENTS: In 4 patients with occlusion of the basilar artery, MRI was performed, including T2-weighted and diffusion-weighted imaging (DWI) sequences and magnetic resonance angiography (MRA) in the short-term phase (<12 hours). Three patients underwent intra-arterial thrombolysis. Clinical outcome was obtained 10 days after symptom onset. RESULTS: The MRA was performed 3.5 to 11.5 hours after symptom onset and showed basilar artery occlusion in all cases. The DWI revealed different patterns of ischemic lesions. In 2 patients, no or only small lesions could be identified; the remaining showed multiple and large lesions within the posterior circulation territory. Initial clinical status was severely impaired in all cases (Rankin scale score, 4-5). Thrombolysis was initiated in 3 patients, leading to successful recanalization in 2. Clinical outcome was favorable in the 2 patients with small DWI lesions and successful reperfusion (Rankin scale score, 2), whereas it was worse in those with large DWI lesions and persisting occlusion (death, persisting coma). CONCLUSIONS: In critically ill patients with acute basilar occlusion, the extent of DWI lesion involvement can be highly variable. Small DWI lesions seem to be associated with a favorable outcome if reperfusion is achieved with thrombolysis. This could potentially be the case independent of time from symptom onset.     

酒后脑梗死的溶栓治疗

目的探讨酒后脑梗死患者的特点、溶栓决策及结局。方法选取2012年9月~2013年6月期间首都医科大学附属北京天坛医院神经内科急诊溶栓绿色通道的酒后脑梗死患者11例,收集患者的临床表现、影像特征、溶栓情况及结局进行回顾性分析。结果 11例酒后脑梗死患者发病0.5~8 h进入急诊溶栓绿色通道,皆为男性,中位数年龄59岁(四分位数间距53.5~60),到达医院时平均中位数发病时间为120 min(四分位数间距45~250)。就诊时主要症状:9例为偏身无力,1例为偏身不自主运动,1例为单肢麻木。小卒中患者8例(73%)。临床过程及转归:2例接受静脉溶栓后明显改善,1例接受动脉溶栓后明显改善,2例拒绝溶栓后自发缓解,3例因症状轻微而未溶栓且自发缓解,2例发病超过3 h的患者因磁共振灌注成像正常而未溶栓,1例发病超过3 h的患者因磁共振弥散加权成像和灌注成像均正常而未溶栓。最终5例在影像上有明确的新发梗死灶。根据急性卒中治疗低分子肝素试验病因分型法(Trial of Org 10172 in Acute Stroke Treatment,TOAST)的分型标准,接受溶栓的3例患者中,2例为大动脉粥样硬化性闭塞,1例为小动脉闭塞;拒绝和未接受溶栓的8例患者均为小动脉闭塞。结论酒后脑梗死多数预后好,有可能从溶栓中获益。酒后脑梗死病因多为小动脉闭塞,少部分是大动脉粥样硬化性闭塞。     

颈内动脉系统脑梗死3～6 h静脉溶栓与动脉溶栓的比较

目的 观察颈内动脉系统梗死患者3～6 h时间窗内静脉溶栓和动脉溶栓治疗的疗效.方法 对34例发病3～4.5 h和18例发病4.5～6 h颈内动脉系统梗死患者,根据头颅磁共振灌注加权成像(PWI)/弥散加权成像(DWI)≥20%,分别行静脉和动脉内超选择性重组组织型纤溶酶原激活剂(rt-PA)溶栓治疗.治疗前后进行卒中量表(NIHSS)评分,并观察血管再通率、出血率,治疗后90 d用修正Raikin量表(MRS)评价临床预后.结果 溶栓后2组患者NIHSS评分较治疗前明显改善(P＜0.05),2组间NIHSS的改善程度差异无统计学意义(P＞0.05).治疗后90 d预后良好率:静脉溶栓组55.9%,动脉溶栓组61.1%,2组间比较差异无统计学意义(P＞0.05).血管再通率:静脉溶栓组47.1%、动脉溶栓组77.8%,2组间比较差异有统计学意义(P＜0.05).出血率:静脉溶栓组17.6%,动脉溶栓组33.3%,2组比较差异无统计学意义(P＞0.05).结论 在头颅MR PWI/DWI不匹配时,颈内动脉系统脑梗死发生3~4.5 h内静脉溶栓与4.5~6 h内动脉溶栓治疗安全有效,两者的效果相当.     

Characterizing the diffusion/perfusion mismatch in experimental focal cerebral ischemia

Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) can rapidly detect lesions in acute ischemic stroke patients. The PWI volume is typically substantially larger than the DWI volume shortly after onset, that is, a diffusion/ perfusion mismatch. The aims of this study were to follow the evolution of the diffusion/ perfusion mismatch in permanent and 60- minute temporary focal experimental ischemia models in Sprague-Dawley rats using the intraluminal middle cerebral artery occlusion (MCAO) method. DWI and arterial spin-labeled PWI were performed at 30, 60, 90, 120, and 180 minutes after occlusion and lesion volumes (mm(3)) calculated At 24 hours after MCAO, and infarct volume was determined using triphenyltetrazolium chloride staining. In the permanent MCAO group, the lesion volume on the ADC maps was significantly smaller than that on the cerebral blood flow maps through the first 60 minutes after MCAO; but not after 90 minutes of occlusion. With 60 minutes of transient ischemia, the diffusion/perfusion mismatch was similar, but after reperfusion, the lesion volumes on ADC and cerebral blood flow maps became much smaller. There was a significant difference in 24- hour infarct volumes between the permanent and temporary occlusion groups.