Proton MR spectroscopy in acute middle cerebral artery stroke.

PURPOSETo investigate the feasibility of performing multisection proton MR spectroscopy in patients with acute stroke, and to determine whether this imaging technique can depict ischemic or infarcted brain regions.METHODSMultisection proton MR spectroscopy, MR imaging, and MR angiography were performed within 24 hours of stroke onset (mean, 12 hours) in 12 patients who had had a stroke of the middle cerebral artery. Spectra were analyzed from brain regions containing T2 hyperintensity abnormalities on MR images, from regions immediately adjacent to these abnormalities, and from anatomically similar contralateral regions. Areas of brain containing lactate were compared with areas of T2 hyperintensities on MR images.RESULTSOne data set was discarded because of excessive artifacts from patient motion. Regions of T2 hyperintensities on MR images were found to contain elevated lactate (all 11 cases) and reduced N-acetyl-aspartate (10 of 11 cases) relative to contralateral measurements. Lactate levels in regions adjacent to T2 hyperintensities were not significantly different from those of infarcted brain. On the other hand, N-acetyl-aspartate was significantly lower in regions of infarction compared with periinfarct tissue. Areas of brain containing elevated lactate significantly exceeded those of T2 abnormality.CONCLUSIONSProton MR spectroscopy is feasible for imaging patients with acute stroke. In the early stages of stroke, tissue containing elevated lactate but no other spectroscopic or MR imaging abnormality can be identified. Such regions may represent an ischemic zone at risk of infarction.     

Lesion patterns in successful and failed thrombolysis in middle cerebral artery stroke

Introduction  

Thrombolysis has been shown to improve neurological recovery in acute stroke. But the response to thrombolysis is variable across patients. We sought to investigate this variability by analyzing the lesion patterns following systemic thrombolysis with recombinant tissue plasminogen activator (rtPA) and tirofiban in middle cerebral artery (MCA) stroke.     

Automated CT segmentation and analysis for acute middle cerebral artery stroke.

BACKGROUND AND PURPOSE: The quantitative nature of CT should make it amenable to semiautomated analysis using modern neuroimaging methods. The purpose of this study was to begin to develop automated methods of analysis of CT scans to identify putative hypodensity within the lentiform nucleus and insula in patients with acute middle cerebral artery stroke. METHODS: Thirty-five CT scans were retrospectively selected from our CT archive (scans of 20 normal control participants and 15 patients presenting with acute middle cerebral artery stroke symptoms). The DICOM data for each participant were interpolated to a single volume, scalp stripped, normalized to a standard atlas, and segmented into anatomic regions. Voxel densities in the lentiform nucleus and insula were compared with the contralateral side at P <.01 using the Wilcoxon two-sample rank sum statistic, corrected for spatial autocorrelation. RESULTS: The quality of the registration for the anatomic regions was excellent. The control group had two false-positive results. The patient group had two false-negative results in the lentiform nucleus, two false-negative results in the insular cortex, and one false-positive finding for the insular cortex. The remainder of the infarcts were correctly identified. The original clinical reading, performed at the time of presentation, produced five false-negative interpretations for the patient group, all of which were correctly identified by the automated algorithm. CONCLUSION: We present an automated method for identifying potential areas of acute ischemia on CT scans. This approach can be extended to other brain regions and vascular territories and may aid in the interpretation of CT scans in cases of hyperacute stroke.     

Transcranial doppler sonography and CT angiography in patients with atherothrombotic middle cerebral artery stroke

BACKGROUND AND PURPOSE: Atherothrombotic disease of the middle cerebral artery (MCA) frequently occurs in Asian populations. This abnormality can be noninvasively assessed with transcranial Doppler sonography (TCD) and computed tomographic angiography (CTA). To our knowledge, the usefulness of TCD sonography compared with CTA in the diagnosis of nonembolic MCA disease has not been studied. METHODS: We prospectively examined 70 patients with clinically suspected atherothrom botic MCA stroke by using TCD sonography and CTA. We excluded patients with a known source of cardiac emboli, significant carotid stenosis, or classic lacunar syndrome. TCD sonography was performed within 2 days of admission, followed by CTA within 7 days after stroke onset. RESULTS: CTA demonstrated MCA stenosis of more than 50% in 57 patients (81%), whereas only 29 patients (41%) had abnormal TCD findings. CTA showed proximal M1 stenosis, distal M1 stenosis, and M2 disease in 29%, 29%, and 24% of the patients, respectively. Stenotic sites differed between patients with normal TCD results and those with abnormal results. TCD findings correlated well with CTA findings in all patients with proximal M1 stenosis. In contrast, TCD sonography correctly depicted distal M1 or M2 disease in only 24% of the patients. CONCLUSION: In this population, CTA is superior to TCD sonography in the diagnosis of MCA disease. Abnormal TCD results are highly suggestive of MCA stenosis. However, normal TCD findings do not exclude such lesions, especially in patients with distal M1 or M2 disease. Because distal M1 and M2 disease was found in half of our patients, TCD sonography should not be used as a method to screen for MCA stenosis.     

Recurrent middle cerebral artery stroke caused by arterial thoracic outlet syndrome and coagulopathy

Thoracic outlet syndrome (TOS) is defined as compression of neurovascular components passing the thoracic outlet. While neurologic compression is the most common form, rare cases of arterial comprssion could result in concerning cerebral thromboembolic events. Here we present a 15-year-old female with repeated left hemiparesis and radiologic signs of cerebrovascular accident (CVA) in right middle cerebral artery. Further investigations revealed stenosis of the right subclavian artery, saccular aneurysm, and occlusion of the right brachial artery which suggested the diagnosis of arterial TOS. Based on this report, we present this diagnosis as a rare but important cause of CVA, especially in young patients.     

Ruptured middle cerebral artery

Summary One case of a ruptured cerebral artery caused by head trauma is reported. The carotid angiogram showed extravasation of contrast medium from the proximal portion of the right middle cerebral artery.

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Traumatische Ruptur der Arteria cerebri media

Zusammenfassung Fallbeschreibung mit angiographisch nachgewiesenem Kontrastmittelaustritt aus den proximalen Abschnitten der Arteria cerebri media.

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Rupture de l'artère cérébrale moyenne

Résumé A propos d'un cas de rupture de l'artère cérébrale par traumatisme cranien. L'angiographie carotidienne montre une extravasation du produit de contraste du segment proximal de l'artère cérébrale moyenne droite.

     

Hyperdense middle cerebral artery sign on CT: efficacy in detecting middle cerebral artery thrombosis

The hyperdense middle cerebral artery sign is a CT predictor of the development of a large cerebral infarct. The limits of detectability were tested in a blinded, then unblinded analysis of CT scans from 25 acute stroke patients. In the initial blinded analysis, sign detection exhibited the following mean values: sensitivity, 78.5%; specificity, 93.4%; positive predictive value, 66%; negative predictive value, 96.4%; accuracy, 91.3%. Kappa statistics analysis indicated poor interobserver agreement (k = .38). Results of unblinded analysis were as follows: sensitivity, 69%; specificity, 94.4%; positive predictive value, 82.8%; negative predictive value, 88.7%; accuracy, 87.3%. There was fair unblinded interobserver agreement (k = .53). Unblinded analysis had a lower false-positive frequency and did not increase the number of true-positive determinations. We conclude that detection of the hyperdense middle cerebral artery sign on CT scans by multiple observers is a sensitive, accurate, and predictive indicator of middle cerebral artery thromboembolism.     

Large middle cerebral artery infarctions and the hyperdense middle cerebral artery sign in patients with atrial fibrillation

PURPOSE: Strokes in patients with atrial fibrillation are often due to large middle cerebral artery (MCA) infarctions, caused by cardiogenic emboli. The purpose of this study was to characterise the large MCA infarctions and to describe the prevalence and prognostic value of the hyperdense middle cerebral artery sign (HMCAS) in patients with atrial fibrillation. MATERIAL AND METHODS: The patient material comprised all 449 patients included in a randomised clinical trial of low molecular-weight heparin versus aspirin in patients with acute ischaemic stroke and atrial fibrillation. Patients with Scandinavian Stroke Scale score <8 were excluded. CT was performed on admission and at day 7, and was evaluated blinded to clinical data. The CT findings on admission were related to functional outcome at 14 days and 3 months, and incidence of cerebral haemorrhage within 7 days. RESULTS: Altogether 66/449 (15%) of the patients had large MCA infarctions. These patients had poorer clinical outcomes, and a higher frequency of haemorrhage on control CT within 7 days (15/59, 26% vs. 43/368, 12%). The HMCAS was found in 32/449 (7%) of the patients. It was significantly more frequent in patients with large MCA infarctions (17/66, 26% vs. 15/383, 4%), and was found most frequently within the first few hours following stroke onset. The HMCAS was associated with poor clinical outcomes and a higher frequency of cerebral haemorrhage, but these effects were partially explained by a preponderance of other risk factors in the HMCAS group. CONCLUSION: Large MCA infarction is a frequent finding in patients with atrial fibrillation. These patients have a high prevalence of the HMCAS, which is an early infarction sign and a marker of a poor prognosis.     

Transluminal angioplasty for middle cerebral artery stenosis in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: Precutaneous transluminal angioplasty (PTA) is currently performed to treat supraaortic atherosclerotic lesions. Our purpose was to evaluate the safety and efficacy of PTA for middle cerebral artery (MCA) stenosis in patients with acute ischemic stroke. METHODS: We performed PTA with the use of a microballoon (2-2.5 mm in diameter and 10-13 mm in length) in 10 consecutive patients (mean age, 48 years) who met the following criteria: high-grade M1 stenosis (> 70%) and mild neurologic deficits (NIH stroke scale < 4) and/or recurrent transient ischemic attacks (TIAs) resistant to anticoagulation, or a large area of hypoperfusion in the MCA territory on brain perfusion SPECT scans. During follow-up, we administered antiplatelet agents and evaluated the status of restenosis by angiography (n = 2), brain perfusion SPECT (n = 4), and/or transcranial Doppler sonography (TCD) (n = 7). RESULTS: Stenotic arteries were successfully dilated in nine of 10 patients. Angioplasty failed in one patient because the balloon could not pass through the tortuous cavernous internal carotid artery. None of the patients experienced either peri- or postangioplasty complications. Residual stenosis was less than 50%, and clinical improvement, including elimination of TIAs in four patients who had suffered resistant TIAs, was observed in all patients; improvement of the cerebral perfusion was also noted in two patients with a large hypoperfusion area in the MCA territory. The average follow-up period was 11 months (range, 2 to 36 months). None experienced recurrent stroke during the follow-up period. TCD revealed decreased flow velocity of the MCA after angioplasty in seven patients. CONCLUSION: PTA of the proximal portion of the MCA seems to be a safe and effective therapeutic technique for the prevention of secondary ischemic stroke.     

大脑中动脉慢性闭塞颅内血流动力学及侧支循环的研究

<正> 大脑中动脉闭塞是引起脑梗死的主要原因之一。经颅多普勒超声(TCD)通过对颅内主要血管的检测,可准确提供颅内血管的血流动力学改变,对大脑中动脉闭塞的诊断及侧支循环的观察具有重要指导意义。1 资料与方法1.1 一般资料收集2007年3月～2010年3月经磁共振血管成像(MRA)明确诊断的大脑中动脉     

Secondary degeneration of the substantia nigra and corticospinal tract after hemorrhagic middle cerebral artery infarction: diffusion-weighted MR findings.

Middle cerebral artery (MCA) infarction involving the striatum can cause secondary degeneration of the substantia nigra and corticospinal tract. We present a patient with subacute hemorrhagic MCA infarction in whom diffusion-weighted MR images showed high signal intensity in the ipsilateral substantia nigra and corticospinal tract. A corresponding apparent diffusion coefficient map revealed a uniformly decreased signal in the same area. This represents secondary degeneration and should not be mistaken for other pathological conditions, such as a new infarction.     

运用3.0T磁共振探讨颈动脉与大脑中动脉斑块负荷的关系

目的应用3.0T磁共振研究急性脑缺血患者颈动脉和患侧大脑中动脉的斑块负荷,探究两者之间的关系。方法 50例经临床和MRI证实为急性前循环缺血的患者在发病1周内行颈动脉和患侧大脑中动脉磁共振多序列检查,测得各血管的管腔面积(LA)、管壁面积(WA)、血管总面积(TVA),并计算出管壁标准化指数(NWI=WA/TVA)。结果①同一患者两侧的颈动脉NWI之间差异无统计学意义(P>0.05);②大脑中动脉M1段的NWI(0.62±0.07)比同侧颈动脉的NWI(0.36±0.06)显著增高(P<0.01);③同侧颈动脉与大脑中动脉M1段的NWI间存在显著的相关性(左侧r=0.89,P<0.001;右侧r=0.79,P<0.001)。结论动脉粥样硬化是一种系统性病变,可以同时累及多个血管床,而急性脑缺血患者以大脑中动脉斑块负荷增加更为显著。     

Tissue at risk in the deep middle cerebral artery territory is critical to stroke outcome

Introduction  

The clinical efficacy of thrombolysis in stroke patients is explained by the increased rate of recanalization, which limits infarct growth. However, the efficacy could also be explained by the protection of specific sites of the brain. Here, we investigate where is this outcome-related tissue at risk using voxel-based analysis.     

Hyperacute ischemic stroke: middle cerebral artery susceptibility sign at echo-planar gradient-echo MR imaging

PURPOSE: To evaluate the accuracy of echo-planar T2*-weighted magnetic resonance (MR) sequences in detection of acute middle cerebral artery (MCA) or internal carotid artery (ICA) thrombotic occlusion. MATERIALS AND METHODS: Forty-two consecutive patients with stroke involving the MCA territory underwent MR imaging within 6 hours after clinical onset. MR examination included echo-planar T2*-weighted, diffusion-weighted (DW), and perfusion-weighted (PW) imaging and MR angiography. Presence or absence of the susceptibility sign on echo-planar T2*-weighted images, which is indicative of acute thrombotic occlusion involving MCA or ICA, was assessed in consensus by two observers blinded to clinical information and other MR imaging data. Differences in lesion volume on DW and PW images between patients with and those without the susceptibility sign were evaluated with the Mann-Whitney test. P <.05 was considered to indicate a significant difference. RESULTS: Thirty patients (71%) had a positive susceptibility sign that correlated with MCA or ICA occlusion at MR angiography in all cases (sensitivity, 83%; specificity, 100%). Mean lesion volume on PW images was higher in patients with a positive susceptibility sign (P =.01), but no significant differences were found in mean lesion volume on DW images. Cases in which the susceptibility sign was identified proximal to MCA divisional bifurcation (27 patients) showed a mean perfusion deficit of 83.9% of the total MCA territory (range, 50%-100%). CONCLUSION: Presence of the susceptibility sign proximal to MCA bifurcation provides fast and accurate detection of acute proximal MCA or ICA thrombotic occlusion.     

Hyperperfusion syndrome with hemorrhage after angioplasty for middle cerebral artery stenosis

Hyperperfusion syndrome is a well-documented complication of carotid endarterectomy, as well as internal carotid artery angioplasty and stent placement. We report a similar complication after distal intracranial (middle cerebral artery [MCA] M2 segment) angioplasty. To our knowledge, this is the first report of hyperperfusion syndrome after intracranial angioplasty of a distal MCA branch.     

Urgent stenting of the M2 (superior) division of the middle cerebral artery after systemic thrombolysis in acute stroke

We report a case of a 54-year-old man who presented with a right middle cerebral artery territory infarct and was treated with systemic thrombolytics. He continued to fluctuate neurologically and, with the use of angiography, was found to have an occlusion of the right M2 artery (superior division). This occlusion was successfully revascularized with a coronary stent.