Microembolic signals after 7 days but not within 24 hours of stroke onset should be predictor of stroke recurrence

BACKGROUND AND PURPOSE: Microembolic signals (MES) on transcranial Doppler ultrasonography (TCD) are occasionally detected in acute ischemic stroke patients and gradually decrease over time. If MES is detectable at 7 days after stroke onset, embolic source lesions may still be active. We hypothesized that presence of MES at 7 days after stroke onset is strongly associated with stroke recurrence. METHODS: Subjects comprised 143 patients with acute ischemic stroke who were prospectively examined for the presence of MES using TCD both within 24 h and at 7 days after stroke onset. Stroke recurrence was assessed within 3 months of stroke onset. The association between presence of MES and stroke recurrence was investigated. RESULTS: MES was detected in 70 of 143 patients (49%) within 24 h of stroke onset and in 34 patients (24%) at 7 days. Stroke recurrence was observed in 6 patients after 7 days and in 10 patients between 7 days and 3 months after stroke onset. Presence of MES within 24 h of stroke was not associated with stroke recurrence (10% for MES-positive vs. 12% for MES-negative, p=0.792). At 7 days after onset, stroke recurrence was more frequent in the MES-positive group at 7 days than in the MES-negative group (24% vs. 7%, p<0.0001). Cox's proportional hazard analysis demonstrated presence of MES as an independent factor of stroke recurrence (hazard ratio, 6.4; 95% confidence interval, 1.4-28; p=0.015). CONCLUSION: Presence of MES detected on TCD at 7 days of stroke onset should be a predictor of stroke recurrence.     

Diffusion weighted MRI imaging and MES detection in the assessment of stroke origin

OBJECTIVES: This study compares the additional benefit of diffusion-weighted MRI (DWI) and microembolus detection by transcranial Doppler ultrasonography (TCD) in the assessment of stroke etiology. METHODS: Fifty-five acute anterior circulation stroke or TIA patients were investigated by both cranial DWI and bilateral TCD of the middle cerebral arteries (1 hour). RESULTS: In one of the 13 patients without acute ischemic lesions visualized on DWI, microembolic signal (MES) detection was positive. However, in 33 out of 44 patients without MES, DWI revealed at least one lesion. In two patients with unilateral territorial infarction and otherwise normal cardiovascular work-up, bilateral MES were found thus localizing the embolic source into the aortic arch or the heart. In a further patient with a dissection, the occurrence of contralateral MES raised doubts on a dissection to be the cause of the infarct. DISCUSSION: There is a contribution of both techniques to the understanding of stroke etiology. The impact of DWI is, however, superior to that of MES detection. Longer TCD recording times may diminish this discrepancy.     

Microembolic signals and clinical outcome in patients with acute stroke – a prospective study

The occurrence of microembolic signals (MES) in patients with transient ischemic attack (TIA) or stroke has already been described; the influence of the time interval between onset of symptoms and transcranial Doppler monitoring (TCD) on the MES rate or MES prevalence and the possible prognostic value of the early detected MES rate on the outcome of TIA or stroke symptoms in a 3 month interval are discussed. In a prospective study we evaluated 61 patients consecutively admitted to our stroke unit after their first ischemic neurological deficit involving the vascular territory of MCA and/or ACA. All of the patients underwent a 30-minute bilateral transcranial Doppler monitoring of their MCAs for the identification of MES. Monitoring was performed within 12.3 + -9.3 (average mean + -SD) hours of stroke onset for the first time, the second time 48 hours after first TCD monitoring. Prognosis for the recovery of neurological deficits was evaluated by using the Barthel index (BI) and Scandinavian Stroke Scale (SSS) at the time of admission of the patient to the stroke unit, and with Barthel indices after one month and after 3 months. As a result, 56% of all patients showed MES in at least one of the two registrations. MES were recorded not only on the symptomatic side. The MES prevalence between both TCD monitorings was significantly different (total MES prevalence: 1st TCD: 26 patients: 2nd TCD: 13 patients; p < 0.04; ipsilateral MES prevalence: 1st TCD: 19 patients; 2nd TCD: 9 patients; p < 0.01). The regression analysis showed a significant influence of the total MES rate on both neurological scores at admission (SSS: 0.03; Barthel index: 0.04), but not for the Barthel scores after one and three months. In conclusion, we found an influence of the time interval between onset of neurological symptoms of TIA or stroke on the MES rate and the prevalence of MES. The prevalence of MES or the MES rate, found after a short time interval to the onset of symptoms, did not have a prognostic value on the outcome of neurological deficits up to a three month follow-up.     

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.     

The differences of clinical parameters between small multiple ischemic lesions and single lesion detected by diffusion-weighted MRI

OBJECTIVES: The cause of small infarction is mainly considered to be intracranial small-vessel disease. However, it is difficult to explain the mechanism of multiple, acute infarctions by small-vessel disease. We examined the differences of clinical parameters between patients with multiple small lesions and single lesion detected by Diffusion-weighted MRI (DWI). MATERIAL AND METHODS: We reviewed the clinical records of 86 consecutive stroke patients with lacunar size ischemic lesions on DWI during the acute stage (within 72 h of onset). The subjects were 55 males and 31 females (mean age 72.4 +/- 9.9 years). Small multiple acute ischemic lesions were defined using the following criteria 1): the lesions were detectable by DWI 2), the diameter of each lesion on DWI was less than 1.5 cm, and 3) more than one vascular territory was involved. Included in the analysis were age, sex, lipoprotein (a) levels, hematocrit, atrial fibrillation (Af), stenosis of middle cerebral artery (MCA), internal carotid artery (ICA) or basilar artery stenosis detected by magnetic resonance angiography (MRA), National Institute of Health Stroke Scale (NIHSS) at admission, and a history of hypertension, diabetes mellitus, hyperlipidemia, and smoking. RESULTS: Twenty-one (24.4%) out of 86 patients with small acute infarctions had multiple acute ischemic lesions. Multiple logistic regression analysis showed that Af and stenosis of ICA or basilar artery were significantly more prevalent in patients with multiple lesions than single lesions. CONCLUSION: Multiple, small lesions visible in DWI are likely to be caused by emboli from heart or atheroma of the large vessels than single small lesion.     

大脑中动脉狭窄患者急性脑梗死发病机制:一项弥散加权磁共振和微栓子监测研究

目的我们前瞻性研究了30例经颅多谱勒超声(TCD)和核磁血管成像(MRA)检查证实大脑中动脉(MCA)狭窄,并在该供血区域出现急性缺血性卒中患者,以探讨MCA狭窄的可能机制。方法全部病人均进行微栓子监测以及弥散加权磁共振(DWI)检查。急性梗死分成单发和多发梗死,梗死部位分成皮层梗死(CI)、交界区梗死(BI)和深穿支动脉梗死(PAI)。微栓子信号(MES)和DWI梗死病灶分别由两位不同的医生在不知道对方资料的情况下确认。结果DWI结果发现急性多发脑梗死和单发梗死各15例(50%)。多发梗死病人中,成链状排列的BI最常见(11例,占73%)。单发梗死中只有PAI是最常见的类型(10例,占67%)。10例(33%)病人检测到MES,每30min内MES的中位数为15(3-102)个。MES在多发梗死中的发生频率(9/15,60.0%)明显高于单发梗死(1/15,6.7%)(P=0.002)。MES的数目能预测DWI上脑梗死的数目(线性回归,调整后R2=0.475,P<0.01)。结论MCA狭窄梗死最常见的原因有两个:①穿支动脉闭塞引起的皮层下小的腔隙性梗死;②由动脉-动脉的栓子不能被清除而造成的多发小梗死,尤其是在交界区更明显。     

Association of ischemic lesion patterns on early diffusion-weighted imaging with TOAST stroke subtypes

BACKGROUND: Different topographic patterns in patients who experience an acute ischemic stroke may be related to specific stroke causes. OBJECTIVE: To determine if lesion patterns on early diffusion-weighted imaging (DWI) are associated with stroke subtypes determined by the TOAST (Trial of ORG 10172 in Acute Stroke Treatment) classification. DESIGN: Cross-sectional study. SETTING: General community hospital.Patients We studied 172 consecutive ischemic stroke patients with a symptomatic lesion on DWI performed within 24 hours of stroke onset. MAIN OUTCOME MEASURES: Lesion patterns on DWI were classified into single lesions (corticosubcortical, cortical, subcortical > or =15 mm, or subcortical <15 mm), scattered lesions in one vascular territory (small scattered lesions or confluent with additional lesions), and multiple lesions in multiple vascular territories (in the unilateral anterior circulation, in the posterior circulation, in bilateral anterior circulations, or in anterior and posterior circulations). RESULTS: We found an overall significant relationship between DWI lesion patterns and TOAST stroke subtypes (P<.001). Corticosubcortical single lesions (P =.01), multiple lesions in anterior and posterior circulations (P =.03), and multiple lesions in multiple cerebral circulations (P =.008) were associated with cardioembolism. Multiple lesions in the unilateral anterior circulation (P =.04) and small scattered lesions in one vascular territory (P =.06) were related to large-artery atherosclerosis. Nearly half (11/23) of the patients with a single subcortical lesion that was 15 mm or larger were classified as having cryptogenic strokes (P =.001), although 9 of these patients had a classic lacunar syndrome without cortical hypoperfusion. CONCLUSIONS: Early DWI lesion patterns are associated with specific stroke causes. Conventional 15-mm criteria for lacunes, however, may underestimate the diagnosis of small-vessel occlusion with DWI.     

经颅多普勒监测微栓子阳性的临床分析及思考

目的探讨微栓子(MES)阳性患者的临床、影像学特点及随访结果。方法对10例微栓子阳性患者的临床资料、出院后随访结果进行回顾性分析。结果患者的平均年龄为(58±14. 09)岁,其中女性患者2例,男性8例;临床主诊断均为缺血性脑血管事件。8例MES阳性侧被检血管为中重度局限性狭窄; 6例颈部血管彩超提示存在不均质回声斑块; 1例患者为心脏瓣膜置换术后,多次监测提示双侧大脑中动脉(MCA)大量MES通过,同时合并右侧颈内动脉闭塞,但未发生脑卒中; 3例经颅多普勒超声–发泡试验阳性,1例可见栓子雨,均不伴血管狭窄。3个月后随访,1例再发MES阳性一侧大面积脑梗死,致瘫痪、失语。3例发泡试验阳性患者MES仍阳性,相同时间内MES通过数量无明显改变。5例患者颈部血管超声呈高、等回声斑块,1例患者为低回声斑块,6例患者认知功能存在不同程度减退。结论 MES阳性与颅内外动脉不稳定斑块或卵圆孔未闭相关,MES阳性患者需关注脑卒中复发及认知功能减退的问题。     

Microembolic signals in systemic lupus erythematosus and other cerebral small vessel diseases

Microembolic signals (MES) are detected by transcranial Doppler (TCD), and are mainly observed in cardiac and large-artery diseases; however they might also be observed in conditions affecting small vessels of the brain. We aimed to review the current medical literature related to MES assessed by TCD in patients with cerebral small vessel disease. We conducted a systematic review in PubMed and selected the articles with information on this topic. Systemic lupus erythematosus (SLE) is the disease with more articles; pooled data showed a frequency of MES of 14.9%. MES were more frequent in SLE patients with antiphospholipid antibodies and ischemic stroke. MES have also been described in other diseases such as primary antiphospholipid syndrome, Sneddon’s syndrome, and Behçet’s disease. Further studies assessing the significance of MES in the pathogenesis of neurological manifestations of these disorders is warranted.     

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.     

Multiple small subcortical infarction required to distinguish from lacunar infarction: evaluation by use of diffusion-weighted imaging]

Lacunar infarctions are small lesions caused by occlusion of the deep and penetrating vessels. Occlusion of such vessels are resulted from thrombosis based on atherosclerotic change. However, we occasionally encounter a patient with lacunar infarction seemed to be caused by embolic mechanism, as who has had previous experience of TIA or presented with clinical symptoms suddenly. Diffusion-weighted imaging (DWI) has high accuracy for depicting small ischemic lesions and discrimination of recent infarctions from old ones. We studied frequency, risk factors and stroke mechanism in the territory of penetrating arteries detected on DWI, and sensitivity of ischemic lesions by DWI as compared with conventional MRI images. Fifty-three consecutive patients with lacunar infarction in the territory of penetrating arteries who admitted to our hospital and were studied by DWI within 24 hours. Nine (17.0%) of 53 patients had multiple high signal lesions on DWI. These lesions were found in single arterial territory in 4 patients and in more than 2 territories in 5 patients. It was presumed that stroke mechanisms were artery to artery or cardiogenic embolism. DWI revealed all 38 hyperintensity lesions, while conventional MRI revealed 35 lesions, although the latter was resulted from retrospectively referring to the DWI finding. Therefore, conventional MRI alone might have been difficult to detect multiple lesions. DWI was enable to distinguish embolic infarction from small vessel lacunar infarction, leading to feasible patient management. Therefore, DWI should be performed in all patients with lacunar infarction, even if neurological finding is correspondent with the conventional MRI finding.     

以急性多发性脑梗死为首发表现的隐匿性躯体恶性肿瘤12例报告

目的研究以急性多发脑梗死为首发表现的隐匿性躯体恶性肿瘤患者的临床表现、实验室检查、影像学、微栓子监测检查特点,探讨其可能的发病机制。方法纳入以急性多发性脑梗死为首发表现的隐匿性躯体恶性肿瘤患者12例,收集其临床资料,分析其实验室血液学、头颅MRI、微栓子监测结果及其治疗和预后。结果所有患者均以局灶性神经功能缺损为主要表现,包括偏瘫、失语、偏身感觉障碍、构音障碍、眩晕、肢体抽搐等。头颅DWI示急性多发脑梗死,病灶播散性分布,不符合单支动脉供血区,同时累及双侧前循环或前后循环。11例行D-dimer检查者8例升高。7例行微栓子监测有5例阳性。隐匿性躯体恶性肿瘤包括:肺癌5例,胰腺癌3例,胃癌、结肠癌、子宫内膜癌、转移性低分化粘液腺癌原发肿瘤部位不明各1例;诊断时就已有远处转移者10例。病程中缺血性卒中复发者7例,急性心肌梗死4例,住院期间死亡3例,预后差。结论对于不符合单支动脉供血区的多发急性脑梗死,需要考虑可能合并隐匿性躯体恶性肿瘤,凝血功能筛查高凝状态和微栓子阳性可能是诊断提示线索。     

Size of PFO and amount of microembolic signals in patients with ischaemic stroke or TIA

Background and purpose:  The inter-relation between the size of patent foramen ovale (PFO) by transesophageal echocardiography (TEE) and the amount of microembolic signals (MES) on transcranial doppler (TCD) is still not determined.
Methods:  The study group comprised of 104 patients with first-ever ischaemic stroke or transient ischemic attack (TIA). Three groups were formed according to the amount of MES on TCD: a small amount of MES (0–10 MES); a moderate amount of MES (countable MES higher than 10); and multiple MES.
Results:  According to TEE, there were 52 patients (50%) with a small PFO, 37 patients (35.6%) with a moderate PFO, and 15 patients (14.4%) with a large PFO. There were 48 patients (46.1%) with a small amount of MES, 34 patients (32.7%) with a moderate amount of MES, and 22 patients (21.1%) with multiple MES on TCD. A strong relationship between the size of the PFO on TEE and the amount of MES on contrast transcranial Doppler was found ( P  < 0.0001), such that the larger the PFO on TEE, the greater the amount of MES on TCD.
Conclusions:  There is a high correlation between the size of the PFO on TEE and the amount of MES on TCD in stroke and TIA patients.     

Differences in number, size and location of intracranial microembolic lesions after surgical versus endovascular treatment without protection device of carotid artery stenosis

Abstract. Background and purpose: The benefit of carotid endarterectomy in symptomatic high-grade stenosis has long been proven. The role of angioplasty as an alternative is still a matter of debate. We compared the occurrence of intraprocedural microembolic signals and ischemic lesions between carotid endarterectomy (CEA) and carotid angioplasty with stent placement (CAS) without a protection device. Methods: 88 patients who underwent a CEA and 41 patients who underwent CAS were prospectively investigated. One day before and after the intervention diffusion weighted MRI-studies were obtained. In 21 CEA and 18 CAS patients transcranial Doppler (TCD) monitoring was performed during the procedure to detect microembolic signals (MES). Results: DWI-lesions could be detected after intervention in 17% of the CEA patients compared with 54% of the CAS patients (p<0.005). The median lesion volume was 0.08cm³ in the CEA group and 0.02cm³ in the CAS group (p<0.001). Ischemic complications consisted of 2 strokes (2.3%) with symptoms lasting more than seven days in the CEA group and 1 stroke (2.4 %) in the CAS group. The median number of MES in the CEA group was 17 versus 61 in the CAS group (p<0.001). No significant correlation was found between the total number of MES and ischemic lesions in either group. Conclusion: A larger number of emboligenic particles with smaller volume is detached during CAS. Additionally DWI lesions were observed in different territories after CAS but not after CEA. Conventional TCD emboli detection is not useful to compare interventional therapies of the carotid arteries.     

Scattered brain infarct pattern on diffusion-weighted magnetic resonance imaging in patients with acute ischemic stroke

BACKGROUND AND PURPOSE: Infarct patterns on brain imaging contribute to the etiologic classification of ischemic stroke. However, the association of specific subtypes of infarcts and etiologic mechanisms is often weak, and acute lesions are frequently missed on initial computed tomography (CT). Diffusion-weighted imaging (DWI) is superior in visualizing acute ischemic lesions as compared to CT and conventional magnetic resonance imaging (MRI). In our prospective study, we addressed the question whether a distinct pattern of infarction on DWI is associated with infarct etiology and clinical outcome. METHODS: Sixty-two patients with clinical signs of acute ischemic stroke and negative acute CT upon admission underwent DWI within 10 days after the ictus. Neurological status was documented using the NIH stroke scale. A scattered lesion pattern was defined by at least 2 separate hyperintense DWI lesions within the territory of one of the major cerebral arteries. Ischemic lesions were defined as acute if the region was demarcated strongly hyperintense in all DW images, and if the apparent diffusion coefficient was below normal. RESULTS: In 32 patients, DWI revealed a scattered lesion pattern, while in 30 patients a single acute lesion was detected. In patients with scattered lesions, potential arterial or cardiac embolic sources were detected in 26 patients (81.3%), as compared to 5 patients (16.6%) in the group with single lesions (chi(2) test, p < 0.0001). The neurological status of patients with scattered lesions improved significantly more than among patients with single lesions (Mann-Whitney test, p < 0.0003). CONCLUSION: A scattered lesion pattern on DWI in patients with acute brain infarction and negative initial CT scan is associated with an embolic etiology and may indicate a favorable clinical outcome.     

急性缺血性卒中患者大脑中动脉狭窄微栓子信号预测再发脑缺血事件

本文是采用经颅多普勒超声(TCD)检测大脑中动脉狭窄(MCA)微栓子信号(MES)的研究,选择了114例MCA狭窄的急性缺血性卒中患者,结果发现22%的患者有MES,平均18个(1～102),重度狭窄(48%)患者较轻中度狭窄者(15%)更易出现MES。平均随访13．6个月(1～32个月),其中12例(12．2%)患者再次出现MCA供血区域的缺血事件(10例卒中,2例TIA)。Cox回归分析显示调整其他卒中高危因素后,MES是再发缺血性卒中/TIA的独立预测因子(P=0．01)。检测MES能够预测MCA狭窄的急性卒中患者脑缺血的复发,因此提出应将MES检测作为常规检查的一部分,这或许能识别那些最可能从抗栓治疗中获益的患者。     

Specific DWI lesion patterns predict prognosis after acute ischaemic stroke within the MCA territory

BACKGROUND: Apart from diffusion-weighted imaging (DWI) lesion volume and diffusion-perfusion mismatching, there is limited information about neuroradiological predictors of early prognosis after an ischaemic stroke. This study sought to identify specific DWI lesion patterns that would help prediction of early prognosis of three different endpoints: unstable hospital course, recurrence of stroke, and poor neurological outcome at 90 days after ischaemic stroke. METHODS: A total of 426 patients with acute cerebral infarcts within the middle cerebral artery territory were prospectively studied. Using the DWI data the patients were divided into six groups (territorial, other cortical, small superficial, internal border zone, small deep, and other deep infarcts), and any recurrent strokes and prognosis over the following 90 days were recorded. RESULTS: DWI lesion pattern was a stronger and more consistent independent outcome predictor than DWI lesion volume. The specific DWI lesion patterns associated with each endpoint differed. An unstable hospital course was frequently observed in patients with internal border zone infarcts, whereas recurrent strokes after the index stroke were commoner in those who had small superficial infarcts (p<0.05 in both cases). Similarly, poor outcome after stroke was associated with older age, severe neurological deficits at admission, and a DWI lesion pattern showing internal border zone infarcts. CONCLUSIONS: The results of the present study indicate that the DWI lesion pattern may help in recognition of the likely differences in the early prognostic endpoints after ischaemic stroke, and DWI analysis may guide targeted interventions to prevent negative outcomes.     

Microembolic signal monitoring in hemispheric acute ischaemic stroke: a prospective study

BACKGROUND AND PURPOSE: There are few data on the occurrence of microembolic signals (MES) in the acute phase of ischaemic stroke. The objective of our work was to systematically study the frequency of MES in non-selected patients with a first-ever hemispheric transient ischemic attack (TIA) or acute cerebral infarction, and to evaluate the clinical usefulness of MES detection. METHODS: 182 consecutive patients with hemispheric TIA or acute cerebral infarction, and 54-age-matched healthy controls were studied. Bilateral transcranial Doppler ultrasound (TCD) monitoring was performed for at least 30 min with a mean time from stroke onset to TCD of 69 h. Stroke severity on admission, early recurrent stroke and dependency on discharge were investigated. RESULTS: MES were detected in 20.5% of patients with arterial sources of embolism, 17. 1% of patients with potential sources of cardioembolism and 5% of patients with cryptogenic stroke. They were not registered, however, in lacunar infarctions (p < 0.001). Stroke severity on admission of patients with MES was greater than that of patients without MES (47. 1 vs. 19.4% with the Canadian Stroke Scale < or =6.5; p = 0.009). Early recurrent stroke was more frequent in patients with MES (11.8%) than in those without MES (4.2%) although the difference was not statistically significant. Multiple logistic regression analysis showed that MES increased the risk of dependency on discharge (odds ratio, 4.2; 95% CI, 1.2-14.9; p = 0.01) independently of age, stroke severity on admission and presence of an arterial or cardiac embolic source. CONCLUSIONS: There is a strong association of MES in the acute phase of stroke with known potential arterial and cardiac embolic sources. MES have an independent predictive value of poor outcome.     

Incidental DWI Lesions in Patients with Recent Small Subcortical Infarctions

ObjectivesIncidental acute ischemic lesions distinct from the primary neurological insult are identified on diffusion-weighted imaging (DWI) in a number of conditions where cerebral microvascular pathology plays a central role. Another major manifestation of cerebral small vessel disease (CSVD) is ischemic stroke named as recent small subcortical infarction (RSSI). In this study, we sought to identify the prevalence and predictors of incidental DWI lesions in patients with RSSI.Materials and MethodsWe retrospectively analyzed a consecutive series of acute ischemic stroke patients with DWI evidence of acute lesions solely localized to perforator artery territories. Images were evaluated for the presence of additional acute or subacute subcortical DWI lesions, apart from the symptomatic lesion. Clinical features including vascular risk factor burden, together with imaging markers of chronic CSVD, were compared among patients with and without incidental acute or subacute lesions.ResultsAmong 396 patients with no alternate stroke etiology additional incidental subcortical DWI bright lesions were identified in 74 (19%) cases. These lesions were primarily localized in the corona radiata, or centrum semiovale. Patients with incidental DWI lesions were more likely to have a history of hypertension, a higher white matter hyperintensities burden in the periventricular and subcortical region, higher perivascular spaces burden in the basal ganglia, multiple cerebral microbleeds, and multiple chronic lacunes. Presence of multiple chronic lacunes (OR 5.98, 95% CI 3.18-11.24) and ≥2 vascular risk factors (OR 2.03, 95% CI 1.05-3.91) stood out as features significantly associated with incidental DWI lesions in multivariate analysis.ConclusionsOur study shows that acute or subacute ischemic lesions can be incidentally detected in approximately one-fifth of patients with RSSI. This observation suggests that the course of CSVD might be more active, temporally and spatially, in a distinct subgroup of RSSI patients, specifically those with a higher chronic lacune and vascular risk factor burden.     

Dynamics and embolic activity of symptomatic intra-cranial cerebral artery stenoses

OBJECTIVE: To investigate the occurrence of microembolic signals (MES) and hemodynamic features in patients with acute symptomatic intracranial cerebral artery stenoses by transcranial Doppler (TCD). MATERIAL AND METHODS: Twelve patients with acute hemispheric ischemic events and corresponding intracranial cerebral artery stenoses as identified by TCD, and exclusion of extracranial or cardiac emboli sources were repeatedly studied by TCD monitoring of the affected and the contralateral vessel. The occurrence of MES and MES clusters (> or =3 MES per second) and of flow velocity changes was examined. RESULTS: Nine patients presented with MES in the affected artery during the first measurement. In seven patients sudden flow velocity changes could be detected in the affected vessel. In five patients these changes were accompanied by MES clusters. MES and velocity changes disappeared in all patients during follow-up, and the degree of stenosis decreased in nine patients. CONCLUSIONS: The high prevalence of MES and sudden velocity changes in acute intracranial cerebral artery stenoses indicates that acute intracranial stenoses may be formed at least in part by mobile thrombotic material.