缺血性脑卒中与血脂水平关系的初步分析

目的研究血脂异常与缺血性脑卒中及其各亚型的关系。方法收集516例缺血性脑卒中患者及131例非缺血性卒中对照组个体的血脂情况,包括血总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL）、高密度脂蛋白（HDL）等指标,对其进行统计分析比较。并将其中131例缺血性脑卒中患者根据TOAST分型标准进行分型,将各亚组的血脂水平与对照组再进行比较。结果缺血性脑卒中组的HDL水平明显低于对照组,TC／HDL比值明显高于较对照组。其余血脂成分,包括TC、TG、LDL则未发现存在显著差异。亚组比较中,大动脉粥样硬化性卒中（LAA）组、心源性脑栓塞（CE）组、小动脉闭塞性卒中或腔隙性卒中（SAO）组的HDL水平明显低干对照组,而他们的TC／HDL比值则明显高于对照。其余血脂成分比较未见统计学差异。其他原因卒中（SOE）及不明原因卒中（SUE）均显示与血脂各成分无相关性。结论HDL在缺血性脑卒中患者明显降低,其保护因素降低可能是卒中发生的原因之一。TC／HDL比值可作为衡量血脂异常与缺血性卒中关系的指标之一。需要进一步进行基于卒中分型基础上的更大样本量的研究。     

Basilar artery occlusive disease in the New England Medical Center Posterior Circulation Registry

BACKGROUND: Most reports on basilar artery (BA) occlusive disease have retrospectively described single cases or small patient series. OBJECTIVE: To assess clinical and vascular features, stroke mechanisms, etiologies, and outcome of moderate to severe BA occlusive disease among 407 patients in the New England Medical Center Posterior Circulation Registry, the largest prospective series of consecutively collected patients with posterior circulation ischemia to date. RESULTS: We studied 87 patients and identified 3 patient groups with distinct vascular, clinical, etiological, and prognostic characteristics: isolated BA disease (39 patients [44.8%]), BA involvement as part of widespread posterior circulation atherosclerosis (36 patients [41.4%]), and embolism to the BA (12 patients [13.8%]). Vascular risk factors were common and often multiple. Most patients (54 [62.1%]) had involvement of the midportion of the BA. Fifty-eight patients (66%) initially had transient ischemic attacks, of whom 34 (58.6%) progressed to stroke. Transient ischemic attacks were usually multiple, lasted for several months, and increased in frequency as the stroke approached. When an infarct was present, the middle posterior intracranial territory was most often involved (66 patients [75.9%]). Outcome was much better than previously assumed. The mortality rate was 2.3%, and 62 patients (almost 75%) had minor or no deficits at follow-up. Outcome was best among patients with widespread atherosclerotic disease and worst in 7; (58.3%, with major disability) of 12 patients with embolism to the BA. Distal territory involvement, embolism, BA occlusion, decreased level of consciousness, tetraparesis, and abnormal pupils were significant predictors of poor outcome. CONCLUSION: Inclusion of patients into 1 of the BA groups and early identification of predictive outcome factors guide diagnostic evaluation and treatment.     

Early spontaneous hematoma in cerebral infarct: is primary cerebral hemorrhage overdiagnosed?

We identified 15 patients (63 +/- 8 years) in whom CT showed no bleeding within 6 hours of stroke onset but showed ganglionic or lobar hemorrhage less than 18 hours later, without visible underlying infarct (early spontaneous intra-infarct hematoma [ESIH]). No patient had antithrombotic therapy or a coagulation disorder, but eight had hypertension. The second CT was prompted by rapid worsening (in 10) or because the first CT was not available (in five). Prior transient ischemic attacks, silent infarcts on CT, and a potential cardiac source of embolism were more common in patients with ESIH than in 200 patients with primary cerebral hemorrhage (PCH) admitted during the same period. Distal occlusions were present in four of five patients who underwent intracranial studies within the first 2 days. Most of these patients probably had embolism with early and extensive bleeding in the ischemic area. Our findings suggest that ESIH may be under-recognized, while PCH may be overdiagnosed.     

大脑中动脉供血区梗死灶形态与可能发病机制的回顾性研究

目的 探索大脑中动脉(MCA)供血区的梗死灶形态与脑卒中可能发病机制之间的关系.方法 回顾性分析了148例连续的急性缺血性脑卒中患者,所有患者均为颈内动脉(ICA)系统脑梗死,DWI显示相应MCA供血区责任病灶,根据血管及心脏检查将患者分为ICA病变组、MCA病变组、ICA+MCA病变组、心源性栓塞组(CE组)及检查结果阴性组(NR组).将梗死灶形态分为单发和多发,前者按部位分为:穿动脉梗死灶(PAI)、皮质支梗死灶(PI)、分水岭梗死灶(BZ)、大面积梗死灶.结果 MCA供血区的梗死灶形态可分为12种;不同病变所致脑卒中的梗死灶形态存在差异(χ2=55.88,P=0.004).但在MCA组、ICA组、MCA+ICA组及CE组中,未发现各自特异的梗死灶形态,仅PAI更多见于MCA组;与NR组相比,ICA组患者中更多出现PAI伴PI(7/27,χ2=6.61,P<0.05),而MCA组和CE组均未见特征性的梗死灶形态.动脉狭窄的程度与梗死灶形态亦存在一定关联,重度ICA病变更多地表现为PAl伴PI(5/16,χ2=7.32,P<0.05);而重度MCA病变则好发PAI伴BZ(4/30,χ2=5.59,P<0.05)及PAI伴PI和BZ(6/30,χ2=6.41,P<0.05).结论 MCA供血区内的梗死灶形态与其颅内动脉病变之间存在一定的关系,揭示脑卒中发生的不同机制,可能与动脉-动脉栓塞、灌注不良有关;我们以检查结果阴性患者为对照比较,尚不能完全揭示MCA供血区内的梗死灶形态和与脑卒中的不同机制之间的相关性.     

Little association between intracranial arterial stenosis and lacunar stroke

Atheromatous middle cerebral artery (MCA) stenosis could cause lacunar stroke by occluding lenticulostriate artery origins, but atheroma is common, and previous studies lacked suitable controls. We aimed to determine if intracranial atheroma was more common in lacunar than in cortical ischaemic stroke. We recruited patients with lacunar stroke and controls with mild cortical stroke, confirmed the stroke subtype with magnetic resonance imaging and used transcranial Doppler ultrasound imaging to record flow velocity and focal stenoses in the basal intracranial arteries 1 month after stroke. We compared ipsi- and contralateral MCA mean flow velocities between stroke subtypes and tested for associations using linear mixed models. Amongst 67 lacunar and 67 mild cortical strokes, mean age 64 and 67 years, respectively, we found no difference in MCA mean flow velocity between cortical and lacunar patients. Increasing age and white matter lesion scores were independently associated with lower MCA flow velocities (0.2 cms(-1) fall in velocity per year increase in age, p = 0.045; 3.75 cms(-1) fall in flow velocity per point increase in white matter lesion score, p = 0.004). We found no intracranial arterial stenoses. MCA atheromatous stenosis is unlikely to be a common cause of lacunar stroke in white populations. Falling velocities with increasing white matter lesion scores may reflect progressive brain tissue loss leaving less tissue to supply.     

Comparison of diffusion-weighted MRI and CT in acute stroke

OBJECTIVE: To compare diffusion-weighted MRI (DWI) and CT with respect to accuracy of localizing acute cerebral infarction; sensitivity, specificity, and interrater reliability for identifying more than one-third middle cerebral artery (MCA) territory involvement; and correlation of acute lesion volume with final infarct volume. METHOD: Nineteen consecutive stroke patients underwent CT and DWI within 7 hours of stroke onset and a follow-up DWI examination 36 hours after symptom onset, which served as the "gold standard" for lesion location and extent of MCA involvement. Each scan was evaluated for acute ischemic lesions by two experienced observers. After 30 days, T2-weighted MRI was obtained for assessment of the final infarct volume. RESULTS: The acute CT and DWI scans were obtained on average 2.6 and 5.1 hours after symptom onset. On DWI the acute lesion was identified correctly in all instances and on CT it was identified correctly in 42 to 63% of patients. Sensitivity for detection of more than 33% MCA involvement was better for DWI (57 to 86%) than for CT (14 to 43%), whereas specificity was excellent for both. Interrater reliability was moderately good for both (kappa, 0.6 for DWI; 0.5 for CT). A positive correlation (r = 0.79; p = 0.001) existed between lesion volume on acute DWI and final infarct volume, whereas no correlation was found between CT volume and final infarct volume. CONCLUSION: When compared with CT, DWI was more accurate for identifying acute infarction and more sensitive for detection of more than 33% MCA involvement. In addition, lesion volume on acute DWI, but not on acute CT, correlated strongly with final infarct volume. Additional studies are required to demonstrate whether these advantages of DWI are clinically relevant in the management of patients with acute stroke.     

颈内和大脑中动脉狭窄与闭塞的梗死类型及卒中机制的研究

目的 研究单侧动脉粥样硬化性MCA/ICA狭窄与闭塞的急性缺血性脑卒中患者在DWI上的梗死类型及发病机制.方法 起病48h内DWI诊断的急性脑梗死伴有动脉粥样硬化性MCA/ICA狭窄与闭塞的131例患者,有潜在心源性栓子患者除外.急性期DWI上梗死病灶分为：（1）单发病灶（小的穿动脉梗死灶;大的穿动脉梗死灶,皮层支梗死,大面积梗死,分水岭梗死）;（2）多发梗死病灶.结果 131例患者,ICA51例,MCA80例.ICA出现最多的梗死类型：穿支动脉伴分水岭梗死,但与MCA比较,皮层支伴分水岭梗死具有统计学意义（8/51,P=0.001）.MCA以穿支动脉伴皮层支梗死最多,且与ICA比较,具有统计学意义（12/80,P=0.003）.MCA中任何皮层支梗死与狭窄程度无关,ICA中任何分水岭梗死与狭窄程度相关.结论 颈内和大脑中动脉狭窄与闭塞在DWI上的梗死类型有明显的不同,提示有着不同的卒中发病机制.     

Spectrum of the posterior inferior cerebellar artery territory infarcts. Clinical-diffusion-weighted imaging correlates

BACKGROUND AND PURPOSE: The clinical, etiological and stroke mechanisms are defined well before but the detailed clinical and etiologic mechanisms regarding to all clinical spectrum of posterior inferior cerebellar artery (PICA) infarcts were not systematically studied by diffusion-weighted imaging (DWI). METHODS: Seventy-four patients with PICA territory ischemic lesion proved by DWI with decreased apparent diffusion coefficient and FLAIR (fluid attenuation inversion recovery) included in our Registry, corresponding to 2% of 3,650 patients with ischemic stroke, were studied. The presence of steno-occlusive lesions in the posterior circulation were sought by magnetic resonance angiography, and reviewed with a three-dimensional rotating cineangiographic method. RESULTS: We found six subgroups of PICA territory infarcts according clinico-topographical relationship: (1) 9 patients with lesion in the territory lateral branch of PICA; (2) 23 patients with an infarct in the territory of medial branch of PICA; (3) 9 patients with a lesion involving both medial and lateral branches of the PICA; (4) 9 patients with cortical infarcts at the boundary zones either between medial and lateral branches of the PICA or between PICA and m/l superior cerebellar artery (SCA); (5) 10 patients with a lesion at the deep boundary zones either between medial and lateral PICA, or between PICA and medial/lateral SCA; (6)14 patients with concomitant multiple lesions in the PICA and in other vertebrobasilar artery territories. The main cause of PICA infarcts was extracranial large-artery disease in 30 patients (41%) patients, cardioembolism and in situ branch disease in 15 patients (20%) each. CONCLUSIONS: Multiple PICA territory lesions on DWI were not uncommon and could be caused by multiple emboli originating from break-up of atherosclerotic plaque in the subclavian/innominate-vertebral arterial system. DWI findings of single or multiple small lesions could account for some cases with transient and subtle cerebellar symptoms which have been considered before as 'vertebrobasilar insufficiency' without morphologic lesion. Different clinical-DWI correlations allow us to determine better definition of the topographical and etiological spectrum of acute PICA territory lesions, which was previously defined by pathological and conventional MRI studies.     

不同大血管闭塞性急性缺血性卒中患者静脉溶栓疗效比较

目的 对不同大血管闭塞所致的急性缺血性卒中患者静脉溶栓疗效进行比较分析,探讨适宜静脉 溶栓治疗的大血管闭塞患者。 方法 本研究的入选患者来自中国急性缺血性卒中溶栓监测登记研究,从中选取所有完成了溶栓 前多模式计算机断层扫描（computed tomography,CT）或磁共振成像（magnetic resonance imaging,MRI）, 且血管成像提示有责任大血管闭塞的患者,对不同大血管闭塞的急性缺血性卒中患者静脉溶栓的有 效性及安全性结局进行比较分析。 结果 共入选122例患者,大脑中动脉闭塞组溶栓后血管再通率为55.2%,而颈内动脉闭塞组为0%, 基底动脉闭塞组为40%。大脑中动脉闭塞组90 d随访生活自理［53.9% vs 21.1%,P =0.007,比值比 （odds ratio,OR）=5.68］及良好预后（42.7% vs 21.1%,P =0.041,OR =3.76）的比例均优于颈内动脉 闭塞组,死亡率低于颈内动脉闭塞组（4.5% vs 47.4%,P <0.001,OR =0.03）,而两组溶栓后的症状 性颅内出血发生率差异无显著性（1.1% vs 0%,P =0.962）。 结论 不同大血管闭塞性急性缺血性卒中患者静脉溶栓效果有明显差异,大脑中动脉闭塞患者静 脉溶栓开通率最高,疗效明显优于颈内动脉闭塞患者。     

Agreement and variability in the interpretation of early CT changes in stroke patients qualifying for intravenous rtPA therapy.

BACKGROUND AND PURPOSE: Ischemic changes identified on CT scans performed in the first few hours after stroke onset, which are thought to possibly represent early cytotoxic edema and development of irreversible injury, may have important implications for subsequent treatment. However, insecurity and conflicting data exist over the ability of clinicians to correctly recognize and interpret these changes. We performed a detailed review of selected baseline CT scans from the NINDS rt-PA Stroke Trial to test agreement among experienced stroke specialists and other physicians on the presence of early CT ischemic changes. METHODS: Seventy baseline CT scans from the NINDS Stroke Trial were read and classified for the presence or absence of various early findings of ischemia by 16 individuals, including NINDS trial investigators, other neurologists, other emergency medicine physicians, and radiology or stroke fellows. CT scans included normal scans and scans from patients who later developed symptomatic intracranial hemorrhage, as well as scans on which the NINDS rt-PA Stroke Trial neuroradiologist identified clear-cut early CT changes. For each CT finding, kappa-statistics were used to assess the proportion of agreement beyond chance. RESULTS: kappa-Values (95% confidence interval [CI]) ranged from 0.20 (-0.20, 0.61) (fair agreement) to 0.41 (0.37, 0.45) (moderate agreement) among the 16 viewers, and the kappa-value was only 0.39 (0.29, 0.49) (fair) in answer to the question "do early CT changes involve more than one third of the MCA [middle cerebral artery] territory?" There was substantial variability within each specialty group and between groups. kappa-Values were only fair to moderate even among physicians experienced in selecting and treating acute stroke patients with rtPA. Observed agreement ranged from 68% to 85%. Physicians agreed on the finding of early CT changes involving >33% of the MCA territory 77% of the time, although the kappa-value of 0.39 suggested only moderate agreement beyond chance. CONCLUSIONS: There is considerable lack of agreement, even among experienced clinicians, in recognizing and quantifying early CT changes. Improved methods of recognizing and quantifying early ischemic brain damage are needed.     

The Usefulness of the TOAST Classification and Prognostic Significance of Pyramidal Symptoms During the Acute Phase of Cerebellar Ischemic Stroke

Cerebellar stroke is a rare condition with very nonspecific clinical features. The symptoms in the acute phase could imitate acute peripheral vestibular disorders or a brainstem lesion. The aim of this study was to assess the usefulness of the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification in cerebellar stroke and the impact of clinical features on the prognosis. We retrospectively analyzed 107 patients with diagnosed ischemic cerebellar infarction. We studied the clinical features and compared them based on the location of the ischemic lesion and its distribution in the posterior interior cerebellar artery (PICA), superior cerebellar artery (SCA), and anterior inferior cerebellar artery (AICA) territories. According to the TOAST classification, stroke was more prevalent in atrial fibrillation (26/107) and when the lesion was in the PICA territory (39/107). Pyramidal signs occurred in 29/107 of patients and were more prevalent when the lesion was distributed in more than two vascular regions (p?=?0.00640). Mortality was higher among patients with ischemic lesion caused by cardiac sources (p?=?0.00094) and with pyramidal signs (p?=?0.00640). The TOAST classification is less useful in assessing supratentorial ischemic infarcts. Cardioembolic etiology, location of the ischemic lesion, and pyramidal signs support a negative prognosis.     

Choice of neuroimaging in perioperative acute stroke management

At the time of this publication, the fast examination time, wide availability, lack of contraindications, and high accuracy for detecting hemorrhage make NCCT the diagnostic study of choice for initial evaluation of patients who have preoperative stroke. NCCT also has a role in excluding patients who will not benefit from IV thrombolysis, including those who have ICH and patients who have ASPECTS less than 7 or ischemic signs exceeding one third of the MCA territory. Because optimal selection of inpatients who have acute stroke mandates not just brain tissue data but also information about the aortic arch, cervical and intracranial vasculature, and cerebral hemodynamics, additional imaging with multimodal CT technology can, in one scanning session, depicts early ischemic changes, demonstrates hypoperfusion/ischemic penumbra, and locates the vascular lesion. When combined with the clinical scenario, the information provided by CT often is sufficient to help clinicians decide on the appropriate treatment, especially determining eligibility for thrombolysis. The rapidly evolving field of neuroradiology will provide a newer armamentarium in the near future. Although MRI can provide more precise information, it is more time consuming and currently should be considered the method of choice for follow-up imaging, rather than initial imaging, in patients who have perioperative stroke.     

Absent middle cerebral artery flow predicts the presence and evolution of the ischemic penumbra

OBJECTIVES: In acute ischemic stroke the pattern of a perfusion-imaging (PI) lesion larger than the diffusion-weighted imaging (DWI) lesion may be a marker of the ischemic penumbra. We hypothesized that acute middle cerebral artery (MCA) occlusion would predict the presence of presumed "penumbral" patterns (PI > DWI), ischemic core evolution, and stroke outcome. METHODS: Echoplanar PI, DWI, and magnetic resonance angiography (MRA) were performed in 26 patients with MCA territory stroke. Imaging and clinical studies (Canadian Neurological Scale, Barthel Index, and Rankin Scale) were performed within 24 hours of onset and repeated at days 4 and 90. RESULTS: MCA flow was absent in 9 of 26 patients. This was associated with larger acute PI and DWI lesions, greater PI/DWI mismatch, early DWI lesion expansion, larger final infarct size, worse clinical outcome (p < 0.01) and provided independent prognostic information (multiple linear regression analysis, p < 0.05). Acute penumbral patterns were present in 14 of 26 patients. Most of these patients (9 of 14) had no MCA flow, whereas all nonpenumbral patients (PI < or = DWI lesion) had MCA flow (p < 0.001). Penumbral-pattern patients with absent MCA flow had greater DWI lesion expansion (p < 0.05) and worse clinical outcome (Rankin Scale score, p < 0.05). CONCLUSIONS: Absent MCA flow on MRA predicts the presence of a presumed penumbral pattern on acute PI and DWI and worse stroke outcome. Combined MRA, PI, and DWI can identify individual patients at risk of ischemic core progression and the potential to respond to thrombolytic therapy beyond 3 hours.     

Abnormal Metabolic Connectivity in Rats at the Acute Stage of Ischemic Stroke

Stroke at the acute stage is a major cause of disability in adults, and is associated with dysfunction of brain networks. However, the mechanisms underlying changes in brain connectivity in stroke are far from fully elucidated. In the present study, we investigated brain metabolism and metabolic connectivity in a rat ischemic stroke model of middle cerebral artery occlusion (MCAO) at the acute stage using ¹⁸F-fluorodeoxyglucose positron emission tomography. Voxel-wise analysis showed decreased metabolism mainly in the ipsilesional hemisphere, and increased metabolism mainly in the contralesional cerebellum. We used further metabolic connectivity analysis to explore the brain metabolic network in MCAO. Compared to sham controls, rats with MCAO showed most significantly reduced nodal and local efficiency in the ipsilesional striatum. In addition, the MCAO group showed decreased metabolic central connection of the ipsilesional striatum with the ipsilesional cerebellum, ipsilesional hippocampus, and bilateral hypothalamus. Taken together, the present study demonstrated abnormal metabolic connectivity in rats at the acute stage of ischemic stroke, which might provide insight into clinical research.     

Lesion patterns and etiology of ischemia in superior cerebellar artery territory infarcts

BACKGROUND AND PURPOSE: Infarcts in the territory of superior cerebellar artery (SCA) are uncommon. The clinical, and etiological mechanisms of different infarct patterns of SCA are not well known. Diffusion-weighted imaging (DWI) is superior to conventional magnetic resonance imaging for detecting acute small and multiple ischemic lesions. METHODS: We studied 60 patients with lesions involving SCA territory proved by DWI, which have been selected from 3,800 patients with first ischemic stroke consecutively admitted to our stroke unit over a period of 5 years. RESULTS: There are 7 distinctive SCA lesion patterns: (1) a lesion was found in the medial (m) branch territory of SCA (mSCA) in 14 patients; (2) a lesion in the lateral (l) branch territory of SCA (lSCA) was seen in 9 patients; (3) a coexisting lesion involving mSCA and lSCA was found in 9 patients; (4) a lesion in cortical borderzones between SCA and m/l branches of the posterior inferior cerebellar artery (PICA) was observed in 6 patients; (5) a lesion in deep borderzones between lSCA and mSCA, and lPICA and mPICA was present in 8 patients; (6) a lesion involving the medial rostral cerebellum between the right and left SCA was found in 4 patients; (7) multiple lesions involving SCA and other vertebrobasilar artery territories were present in 10 patients. The main cause was possible artery-to-artery embolism from atherosclerotic vertebrobasilar arteries to distal branches of SCA in 20 patients (33%). Fourteen patients had a source of cardioembolism (23%), and 6 patients (8%) had concomitant atherosclerotic vertebrobasilar artery disease and a source of cardioembolism. CONCLUSIONS: An acute ischemic lesion in the SCA territory is mainly multiple. The lSCA territory was the most involved area. Small territorial infarcts were frequently associated with large territorial SCA infarcts. Borderzone SCA infarcts occurred in one third of the patients with transient benign symptoms. Mass effects are unusual despite the large amount of SCA involvement. Our results supported the fact that embolism is the predominant stroke mechanism in the SCA territory infarction.     

Computed Tomography Angiographic Correlates of Early Computed Tomography Signs in Acute Ischemic Stroke

BACKGROUND AND PURPOSE: Early computed tomography (CT) signs of stroke signify major arterial occlusion. CT angiogram (CTA) is useful in detecting major arterial occlusion and may help triaging patients for intra-arterial thrombolysis. The correlation between the early signs of stroke and arterial occlusion on CTA was studied. METHODS: Consecutive patients with suspected acute anterior circulation ischemic stroke presenting within 6 hours of symptom onset underwent noncontrast CT of the head followed by CTA. The scans were later reviewed for evidence of early signs of stroke on CT scan and intracranial arterial occlusion on CTA. RESULTS: Sixteen of 65 patients had arterial occlusion on CTA; 12 (75%) of these showed the early CT signs of stroke. All the early signs except M2 "dot" sign significantly correlated with middle cerebral artery (MCA) occlusion on CTA. Hyperdense MCA sign was the only independent predictor of a MCA occlusion. CONCLUSION: In a small sample, early CT signs of stroke strongly correlated with arterial occlusion, with hyperdense MCA sign being the most predictive of a MCA occlusion.     

Acute hemispheric stroke: Correlation between three-dimensional transcranial Doppler, MR-angiography, CT and clinical findings

We examined 50 ischemic stroke patients and 67 controls free of vascular disease, intra- or extracranial. We assessed all subjects clinically by neurological examination (quantified on the Canadian Neurological Scale or CNS), by three-dimensional transcranial Doppler sonography (TCD-3D) and by computed tomography (CT) within 24 h of the acute event, repeating CT 15 days later. 15 patients also underwent magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). We used the following Doppler parameters: interhemispheric asymmetry index (AI), mean flow velocity (mV) and pulsatility index (PI) for the middle cerebral artery (MCA). The difference between patients and controls on analysis of the variance (ANOVA) in respect of AI was significant: F=50.8, p<0.0001. The CNS-AI correlation was equally valid: r=−0.56, p<0.001. The CNS-CT correlation proved to be highly significant: r=−0.72, p<0.0001. TCD-3D allowed quantitative evaluation of the hemodynamic changes and of the collateral blood supply and proved to be a sound method for the investigation of ischemic stroke, correlating well with the clinical findings, MRA and lesion size on CT. Paper presented at the National Congress at Sorrento in 1991 and selected by the Editorial Board of the Journal     

Environmental enrichment reverses learning impairment in the Morris water maze after focal cerebral ischemia in rats

Cognitive impairment is common after ischemic stroke. In rodent stroke models using occlusion of the middle cerebral artery (MCA) this is reflected by impaired spatial memory associated with the size of the ischemic lesion. Housing in an enriched environment enhances brain plasticity and improves recovery of sensorimotor functions after experimental stroke in rats. In this study we report that postischemic housing in an enriched environment also attenuates the long-term spatial memory impairment after MCA occlusion and extinguishes the association between spatial memory and infarct volume. An enriched environment did not significantly alter the expression of selected neuronal plasticity-associated genes 1 month after MCA occlusion, indicating that most of the adaptive changes induced by an enriched environment have already occurred at this time point. We conclude that the attenuated memory impairment induced by environmental enrichment after MCA occlusion provides a useful model for further studies on the neurobiological mechanisms of recovery of cognitive functions after ischemic stroke.     

Is TEE useful in patients with small subcortical strokes?

Although the role of transesophageal echocardiography (TEE) in the investigation of stroke mechanism is well established, the value of this test in patients with lacunar presentation is unclear. Review of 214 patients with acute cerebral ischemia referred for TEE to exclude cardioaortic sources of embolism after non-diagnostic basic work-up including carotid ultrasound and transthoracic echocardiography. TEE was considered positive when it showed large or complex aortic arch plaques, left atrial thrombus, mitral or aortic valve vegetations, or patent foramen ovale with atrial septal aneurysm. Multivariate regression analysis was performed to assess the value of lacunar syndrome and radiological small subcortical infarctions in predicting TEE result. Predictive values and likelihood ratios for these variables were calculated. Fifty-two patients (24%) had positive TEE. The most common embolic source was large or complex aortic plaques in 19% of patients. Neither clinical presentation with lacunar syndrome nor the presence of small subcortical infarction on CT scan predicted a negative TEE result on univariate or multivariate analysis. However, the combination of lacunar syndrome with radiological small subcortical infarction was uniformly associated with negative TEE (P=0.01; negative predictive value 100%). The combination of lacunar syndrome with small subcortical radiological infarct predicts the absence of cardioaortic sources of embolism on TEE in patients with acute cerebral ischemia.     

Lesion patterns and mechanism of ischemia in internal carotid artery disease: a diffusion-weighted imaging study

CONTEXT: Although embolism and low-flow phenomenon are the 2 main mechanisms of stroke in internal carotid artery (ICA) occlusive disease, the mechanism of border-zone infarction remains controversial. Diffusion-weighted imaging (DWI) can more easily detect small or multiple ischemic lesions than conventional imaging. OBJECTIVES: To investigate the ischemic lesion patterns on DWI and to discuss the mechanisms of stroke in ICA disease. DESIGN: Case series. SETTING: A tertiary referral center. PATIENTS: We enrolled 35 consecutive patients who had an acute ischemic stroke and (> or = 70%) stenosis or an occlusion of the extracranial ICA confirmed by cerebral angiography and an acute relevant stroke lesion on DWI within 1 week of onset, but without cardiac sources of embolism and tandem intracranial arterial disease. MAIN OUTCOME MEASURES: The lesion pattern on DWI was categorized as territorial or border zone. Multiple ischemic lesions were defined as noncontiguous lesions on DWI in more than 1 vascular territory. RESULTS: There were 3 distinctive stroke lesion patterns. (1) A territorial lesion without a border-zone lesion was found in 21 patients: superficial and superficial territorial in 9, superficial and deep territorial in 7, and single in 5. (2) A border-zone lesion with or without a territorial lesion was found in 10 patients: border zone and territorial in 9 and border zone alone in 1. (3) Bilateral hemispheric lesions were found in 4 patients. Multiple ischemic lesions were found in 29 (82.9%) of the 35 patients. No patient had episodes of hemodynamic compromise. CONCLUSIONS: An acute ischemic lesion in ICA occlusive disease is mainly multiple. Border-zone infarction was mostly associated with territorial infarction. These results support the fact that embolism is the predominant stroke mechanism in ICA occlusive disease.