Middle Cerebral Artery Branch Occlusion Research Articles

Ischemic Stroke Secondary to Middle Cerebral Artery Branch Occlusion From a Thrombosed Saccular Aneurysm

Ischemic Stroke Secondary to Middle Cerebral Artery Branch Occlusion From a Thrombosed Saccular Aneurysm

Factors predicting poor outcome at discharge in stroke patients with middle cerebral artery branch occlusion

ObjectivesTo better determine the usefulness of mechanical thrombectomy for stroke patients with middle cerebral artery (MCA) branch occlusion, we investigated predictive factors related to poor outcome in acute, MCA branch occlusion stroke patients who had not undergone mechanical thrombectomy. Patients and methodsWe retrospectively evaluated 204 consecutive acute stroke patients with MCA branch (M2-M4) occlusion. Two groups, based on activity of daily living scores at discharge, were compared: a dependent outcome group (mRS 3–6; n = 109) and an independent outcome group (mRS 0–2; n = 95), and the factors related to dependent outcomes at discharge determined. ResultsThe dependent group was older, had higher National Institutes of Health Stroke Scale (NIHSS) scores on admission, higher serum D-dimer and brain natriuretic peptide levels, and lower Alberta Stroke Program Early CT scores (ASPECTS) and rates of intravenous thrombolysis than the independent group. In multivariate analysis, age (OR 1.06; 95%CI 1.03–1.10), admission NIHSS score (OR 1.12; 95%CI 1.05–1.19), ASPECTS (OR 0.56; 95%CI 0.40–0.79), and intravenous thrombolysis (OR 0.22; 95%CI 0.08–0.57) were related to dependent outcomes. Decision curve analysis demonstrated that admission NIHSS scores were better predictors of dependency for threshold probabilities from 0.25 to 0.46. The optimal cutoff scores for predicting dependency were ≥8 (sensitivity 0.76, specificity 0.62) for the admission NIHSS score. ConclusionsAdmission NIHSS scores might be useful predictors of dependent outcomes at discharge in acute ischemic stroke patients with MCA branch occlusion.

Assessment of collateral blood flow in patients with distal branch occlusion of the middle cerebral artery

PurposeAim of this study was to evaluate the collateral blood flow between more distal branches of the middle cerebral artery (MCA) in the case of peripheral MCA branch occlusion on dynamic 4D angiograms. We sought to individually predict the finally resulting infarction volume with regard to the extent of collateral blood flow. MethodsOverall, 35 acute ischemic stroke patients with peripheral MCA branch occlusion were included. Volumes of the ischemic infarctions and perfusion deficits were measured on diffusion-weighted images DWI and time-to-peak TTP (> 4 s). Collateral flow on 4D MR angiograms were classified as previously specified. ResultsOn DWI, the ischemic lesions had a mean volume of 3.4 ± 15.1 mL while the mean volume on TTP (> 4 s) was significantly larger 22.0 ± 18.1 mL (P < 0.001). On dynamic 4D angiograms we observed grade 1 in 8 (22.9%), grade 2 in 4 (11.4%), grade 3 in 10 (28.6%), and grade 4 in 13 (37.1%) patients. In comparison to patients with better collateralization (grade 3–4) patients with less sufficient collateralization (grade 0–2) demonstrated larger infarction volumes on initial (11.1 mL (IQR 2.9–35.5) vs. 2.1 mL (IQR 0.5–4.5), P = 0.03) and follow-up DWI (15.5 mL (IQR 12.6–23.3) vs. 1.9 mL (IQR 0.5–4.5), P = 0.03) with prominent infarction growth (7.4 mL (IQR 2.6–10.1) vs. 0.9 mL (IQR 0.2–2.6), P = 0.08). ConclusionsIn the majority of cases with distal MCA branch occlusion a good collateral blood flow has been observed. Nevertheless, in approximately one quarter of patients an insufficient collateral blood flow has been detected that was associated with substantial infarction growth.

Preserved Collateral Blood Flow in the Endovascular M2CAO Model Allows for Clinically Relevant Profiling of Injury Progression in Acute Ischemic Stroke.

Interventional treatment regimens have increased the demand for accurate understanding of the progression of injury in acute ischemic stroke. However, conventional animal models severely inhibit collateral blood flow and mimic the malignant infarction profile not suitable for treatment. The aim of this study was to provide a clinically relevant profile of the emergence and course of ischemic injury in cases suitable for acute intervention, and was achieved by employing a M2 occlusion model (M2CAO) that more accurately simulates middle cerebral artery (MCA) occlusion in humans. Twenty-five Sprague-Dawley rats were subjected to Short (90 min), Intermediate (180 min) or Extended (600 min) transient M2CAO and examined longitudinally with interleaved diffusion-, T2- and arterial spin labeling perfusion-weighted magnetic resonance imaging before and after reperfusion. We identified a rapid emergence of cytotoxic edema within tissue regions undergoing infarction, progressing in several distinct phases in the form of subsequent moderation and then reversal at 230 min (p < 0.0001). We identified also the early emergence of vasogenic edema, which increased consistently before and after reperfusion (p < 0.0001). The perfusion of the penumbra correlated more strongly to the perfusion of adjacent tissue regions than did the perfusion of regions undergoing infarction (p = 0.0088). This was interpreted as an effect of preserved collateral blood flow during M2CAO. Accordingly, we observed only limited recruitment of penumbra regions to the infarction core. However, a gradual increase in infarction size was still occurring as late as 10 hours after M2CAO. Our results indicate that patients suffering MCA branch occlusion stand to benefit from interventional therapy for an extended time period after the emergence of ischemic injury.

Hemodynamic changes in a rat parietal cortex after endothelin-1-induced middle cerebral artery occlusion monitored by optical coherence tomography.

A blockage of the middle cerebral artery (MCA) on the cortical branch will seriously affect the blood supply of the cerebral cortex. Real-time monitoring of MCA hemodynamic parameters is critical for therapy and rehabilitation. Optical coherence tomography (OCT) is a powerful imaging modality that can produce not only structural images but also functional information on the tissue. We use OCT to detect hemodynamic changes after MCA branch occlusion. We injected a selected dose of endothelin-1 (ET-1) at a depth of 1 mm near the MCA and let the blood vessels follow a process first of occlusion and then of slow reperfusion as realistically as possible to simulate local cerebral ischemia. During this period, we used optical microangiography and Doppler OCT to obtain multiple hemodynamic MCA parameters. The change trend of these parameters from before to after ET-1 injection clearly reflects the dynamic regularity of the MCA. These results show the mechanism of the cerebral ischemia-reperfusion process after a transient middle cerebral artery occlusion and confirm that OCT can be used to monitor hemodynamic parameters.

Middle cerebral artery branch occlusion mimicking an aneurysm.

Middle cerebral artery branch occlusion mimicking an aneurysm.

Leukoaraiosis Predicts Cortical Infarct Volume After Distal Middle Cerebral Artery Occlusion

Leukoaraiosis (LA) predominantly affects the subcortical white matter, but mounting evidence suggests an association with cortical microvascular dysfunction and potentially decreased cortical ischemic tolerance. Thus, we sought to assess whether preexisting LA is predictive of the cortical infarct volume after middle cerebral artery branch occlusion and whether it relates to a worse outcome. We analyzed data from 117 consecutive patients with middle cerebral artery branch occlusion as documented by admission computed tomography angiography. Baseline clinical, laboratory, and outcome data, as well as final cortical infarct volumes, were retrospectively analyzed from a prospectively collected database. LA severity was assessed on admission computed tomography using the van Swieten scale grading the supratentorial white matter hypoattenuation. Infarct volume predicting a favorable 90-day outcome (modified Rankin Scale score≤2) was determined by receiver operating characteristic curves. Multivariable linear and logistic regression analyses were used to identify independent predictors of the final infarct volume and outcome. Receiver operating characteristic curve analyses indicated that a final infarct volume of ≤27 mL best predicted a favorable 90-day outcome. Severe LA (odds ratio, 11.231; 95% confidence interval, 2.526-49.926; P=0.001) was independently associated with infarct volume>27 mL. Severe LA (odds ratio, 3.074; 95% confidence interval, 1.055-8.961; P=0.040) and infarct volume>27 mL (odds ratio, 9.156; 95% confidence interval, 3.191-26.270; P<0.001) were independent predictors of a poor 90-day outcome (modified Rankin Scale, 3-6). The presence of severe, subcortical LA contributes to larger cortical infarct volumes and worse functional outcomes adding to the notion that the brain is negatively affected beyond LA's macroscopic boundaries.

Abstract W P110: Preexisting Cerebral Small Vessel Disease Increases Cortical Infarct Volume after Distal Middle Cerebral Artery Occlusion

Background: Cerebral small vessel disease (cSVD) predominantly affects the subcortical white matter. However, little is known about its impact on cortical ischemic susceptibility. We sought to assess whether preexisting cSVD is predictive of the cortical infarct volume following middle cerebral artery (MCA) branch occlusion and whether it relates to a worse 90-day outcome. Methods: We analyzed data from 117 consecutive patients with MCA branch occlusion as documented by admission computed tomography (CT)-angiography. To avoid potential confounding, we excluded patients with subcortical infarction. Baseline clinical, laboratory, and outcome data as well as final cortical infarct volumes on follow-up imaging were retrospectively analyzed from a prospectively collected database. Severity of cSVD was assessed on admission CT using the van Swieten scale (VSS), grading the white matter lesions on a 3-point scale from 0 (absent) to 4 (severe). We also dichotomized the degree of cSVD (VSS 0-2 [absent to moderate] vs. 3-4 [severe]) for statistical purposes. Multivariable linear and logistic regression analyses were used to identify independent predictors of the final infarct volume. Results: A final infarct volume of ≤27 mL best predicted a favorable 90-day outcome (mRS≤2) as determined by receiver operating characteristic curves. Severe cSVD (OR 7.434; 95%-CI 1.549-35.676; p=0.012) was independently associated with infarct volume &gt;27 mL. Patients with severe cSVD had significantly larger cortical lesion volumes compared to patients without (Figure1A). Severe cSVD (OR 3.027; 95%-CI 1.013-9.048; p=0.047) and infarct volume &gt;27 mL (OR 9.038; 95%-CI 1.997-40.899; p=0.004) were independent predictors of a poor 90-day outcome (mRS 3-6; Figure 1B). Conclusion: Severe subcortical cSVD contributes to larger cortical infarct volumes and worse functional outcome adding to the notion that the brain is negatively affected beyond cSVD ‘s macroscopic boundaries.

Abstract WP169: Endovascular Recanalization For The Total Occlusion Of The Internal Carotid Artery At Subacute To Chronic Stage: Clinical Outcome And Pitfalls

Objective: The efficacy and pitfalls of endovascular recanalization for totally occluded internal carotid occlusion were evaluated. Materials and methods: Twenty-five cases (twenty six lesions) of symptomatic internal carotid occlusion with hemodynamic compromise or recurrent symptoms were treated at the subacute to chronic stage using an endovascular technique. At the same period, total 1200 carotid artery stenting was performed in our group. Parodi’s embolic protection system or modified Parodi’s technique was used during the recanalization procedure to prevent embolic stroke by reversing the flow from the distal internal carotid artery to the common carotid artery. Results: Recanalization of the occluded ICA was possible in 23/26 (88.5%) lesions. The occlusion points were cervical internal carotid artery : 19, and petrous - cavernous ICA : 4 in successfully recanalized cases. The patient’s ischemic symptom disappeared completely after the treatment and new ischemic symptoms did not appear related to the treated leision. Single photon emission computed tomography findings demonstrated the improvement of hemodynamic compromise in all cases with hemodynamic compromise. One case (4.3%) caused right middle cerebral artery branch occlusion during the procedure but his neurological symptoms were stable because of preexisting hemiparesis. One case (4.3%) demonstrated asymptomatic re-occlusion at the treated site. Discussion: Endovascular recanalization was possible and effective to improve hemodynamic compromise, although the incidence of this treatment is only 2.2% of the total 1200 carotid artery stenting in our series. However, there still several problems existed, such as hyperperfusion syndrome after recanalization, cerebral embolism during the treatment, and durability after treatment, and difficult identification of the occlusion point before the treatment. Conclusion: Endovascular recanalization using an embolic protection device can be considered as an alternative treatment for the symptomatic internal carotid occlusion with hemodynamic compromise or refractory to antiplatelet therapy, even in the subacute to chronic stage of the illness.

Endovascular recanalization of the completely occluded internal carotid artery using a flow reversal system at the subacute to chronic stage

The efficacy and pitfalls of endovascular recanalization were evaluated in cases of internal carotid artery (ICA) occlusion in the subacute to chronic stage. Fourteen cases (15 lesions) of symptomatic ICA occlusion with hemodynamic compromise or recurrent symptoms were treated at the subacute to chronic stage using an endovascular technique. The Parodi embolic protection system was used during the recanalization procedure to prevent embolic stroke by reversing the flow from the distal ICA to the common carotid artery. Recanalization of the occluded ICA was possible in 14 of 15 lesions. The occlusion points were 10 cervical ICAs and 4 petrous/cavernous ICAs in successfully recanalized cases. Ischemic symptoms disappeared completely after the treatment, and new ischemic symptoms did not appear related to the treated lesion. Single photon emission computed tomography findings demonstrated the improvement of hemodynamic compromise in all cases. One case showed right middle cerebral artery branch occlusion during the procedure, but this patient's neurological symptoms were stable due to preexisting hemiparesis. Endovascular recanalization was possible and effective in improving hemodynamic compromise. However, there are still several problems with this technique, such as hyperperfusion syndrome after recanalization, cerebral embolism during treatment, durability after treatment, and identification of the occlusion point before treatment. Endovascular recanalization using an embolic protection device can be considered as an alternative treatment for symptomatic ICA occlusion with hemodynamic compromise or refractoriness to antiplatelet therapy, even in the subacute to chronic stage of the illness.

Middle cerebral artery branch occlusion mimicking a saccular aneurysm on 3D digital subtraction angiography

The angiographic appearance of an intracranial arterial occlusion is typically distinct from that of a saccular aneurysm, with only a few reported cases of occlusion simulating aneurysm. At the same time, a small percentage of symptomatic intracranial aneurysms present with a stroke. Accurate diagnosis of these conditions is crucial, as their treatment differs. The authors report on a case of middle cerebral artery occlusion that mimicked the appearance of an aneurysm on angiography in the setting of acute stroke. The true diagnosis was not elucidated until repeated angiography 6 months later revealed recanalization of the previously occluded middle cerebral artery branch. This angiographic pitfall is important to consider when acute stroke is suspected as the mode of presentation of a saccular aneurysm.

A Digital Map of Middle Cerebral Artery Infarcts Associated With Middle Cerebral Artery Trunk and Branch Occlusion

Knowledge of the topographic distribution of infarcts of the middle cerebral artery (MCA) may give insight into the limits of the arterial territory and infarct mechanism and may influence the decision to use thrombolytic therapy. We describe the creation of a digital atlas of MCA (DA-MCA) infarction associated with MCA branch and trunk occlusion using magnetic resonance (MR) techniques. Hemispheric infarcts, with evidence of MCA trunk or branch occlusion, were manually segmented into binary images, linearly registered into a common stereotaxic coordinate space, and averaged to yield the probability of involvement by infarction at each voxel. Comparisons were made with existing maps of the MCA territory. Twenty-eight patients with median age of 74 years (range, 26 to 87 years) were studied. On the DA-MCA, the highest frequency of infarction was within the striatocapsular region, centrum semiovale, and the insula. The mean and maximal MCA infarct volumes were 195.5 cm3 and 366.3 cm3, respectively. Comparison with published maps showed that the most common difference from the DA-MCA was in the superomedial extent of the MCA territory. Some maps showed the MCA territory reaching the interhemispheric fissure, whereas in the DA-MCA it did not. There was a lower variability in the anterior boundary of the MCA territory compared with its posterior counterpart. We have created a digital atlas of MCA infarction using MR imaging techniques. This approach may be useful to establish the distribution of the MCA and other arterial territories and the border zones between them with greater certainty.

Diagnosis of middle cerebral artery occlusive lesions with contrast-enhanced transcranial color-coded real-time sonography in acute stroke

It is useful to evaluate the occlusive lesions of middle cerebral artery (MCA) occlusion with transcranial color-coded real-time sonography (TCCS). However, TCCS criteria for locating the site of the MCA occlusion has, as yet, remained unclear. The aim of the present study was to establish TCCS criteria for MCA occlusive lesions. We prospectively performed contrast-enhanced TCCS (CE-TCCS) in 75 consecutive acute stroke patients within 24 h of digital subtraction angiography. Patients were divided into four groups: occlusion of the MCA stem (MO group, n=12); occlusion of the MCA branch (MBO group, n=10); stenosis of the MCA stem (MS group, n=9); and no occlusive or stenotic lesions (control group, n=44). The following parameters were measured: peak systolic velocity (PSV) and end diastolic velocity (EDV) of bilateral MCA stems, and ED-ratio (the side-to-side ratio of the EDV). We establish the CE-TCCS criteria for MCA occlusive lesions using the sensitivity-specificity curve analysis. A PSV of 170 cm/s distinguished MCA stenosis from other groups (positive and negative predictive values and the accuracies were 100%, 99.0% and 99.1%, respectively). An EDV of 26 cm/s differentiated MO or MBO from the other groups (positive and negative predictive values and the accuracies were 84.6%, 100% and 96.5%, respectively). An ED-ratio of 2.5 discriminated MO from the MBO group (positive and negative predictive values and the accuracies were 88.9%, 85.7% and 87.5%, respectively). Measurement of MCA stem flow velocity with CE-TCCS can identify MCA stem stenosis and occlusion, as well as MCA branch occlusion.

Contrast-enhanced transcranial color-coded sonography in acute hemispheric brain infarction.

The aim of the present study was to investigate the diagnostic potential of contrast-enhanced transcranial color-coded real-time sonography (CE-TCCS) in otherwise ultrasound-refractory acute stroke patients with an ischemia in the territory of the middle cerebral artery (MCA). Furthermore, correlations of CE-TCCS findings with clinical, angiographic, and CT results were investigated. In 90 acute stroke patients with inadequate insonation conditions in unenhanced transcranial color-coded real-time sonography (TCCS) examinations, CE-TCCS, clinical, angiographic, and CT examinations were performed within 12 hours, 36 hours (CE-TCCS only), and 1 week after onset of clinical symptoms. A CT angiography (CTA) as reference method was available in 39 individuals. After application of a galactose-based echo-enhancing agent, the portion of conclusive ultrasound examinations of the MCA, as manifested by an MCA occlusion, decreased or increased flow velocity (FV), and symmetrical MCA FV, was evaluated. CE-TCCS findings on admission and during follow-up were correlated with infarction size as demonstrated on follow-up CT, and clinical findings were assessed by use of the European Stroke Scale. Adequate diagnosis was achieved in 74 of 90 patients (82%) by the use of echo contrast agents. MCA occlusion or reduction of MCA FV was found in 20 and 27 patients, respectively. MCA occlusion was confirmed by CTA in 17 cases. In one individual, false-positive diagnosis of MCA occlusion was made according to ultrasound criteria. In 5 patients with MCA occlusion, vessel recanalization was observed during follow-up; 15 of 27 patients with decreased flow velocities showed normalization after the third examination that was associated with a significantly better clinical outcome (P<0.0001). Furthermore, MCA occlusion or decreased FV in the first 12 hours were associated with significantly larger infarctions in the MCA territory compared with normal CE-TCCS findings (P<0.0001). CE-TCCS enables adequate diagnosis in approximately 80% of acute hemispheric stroke patients with insufficient unenhanced TCCS examinations. It is a reliable diagnostic tool regarding MCA mainstem and branch occlusions. Because this method conveys useful information concerning cerebral tissue and clinical prognosis, it may be useful to identify those patients who benefit most from local or intra-arterial thrombolytic therapy.

Effect of N-methyl-D-aspartate and inhibition of neuronal nitric oxide on collateral cerebral blood flow after middle cerebral artery occlusion.

To study the role of N-methyl-D-aspartate (NMDA) receptor activation and selective inhibition of neuronal nitric oxide synthase with 7-nitroindazole (7-NI) on blood flow to collateral-dependent tissue (CDT) after middle cerebral artery (MCA) occlusion. A left craniotomy was performed in each of 11 dogs with the animals under halothane anesthesia. A branch of the MCA was occluded and cannulated distally for determination of CDT, using a "shadow flow" technique. Cerebral blood flow (CBF) and vascular pressures were measured and used to calculate vascular resistance. Our shadow flow model has the ability to identify an area of CDT, with minimal contamination from overlap flow within a morphologically identified "risk area" for MCA branch occlusion. NMDA increased blood flow to CDT by 56.2%, while normal ipsilateral and contralateral cerebrum increased by at least 35% from baseline. 7-NI caused a significant drop in regional CBF, with the greatest drop of 41.7% occurring in the CDT. Normal ipsilateral and contralateral CBF was reduced by 31.7 and 23.9%, respectively. The dilator response to NMDA was significantly attenuated after 7-NI administration, except in CDT where flow increased ("inverse steal"). Cerebral vascular resistance decreased in response to NMDA and increased with 7-NI. Neuronal nitric oxide production seems to play an important role in regulating vascular tone and CBF to CDT after MCA occlusion. Selective preservation of blood flow to CDT seems to be mediated by NMDA receptor activation but independent of neuronal nitric oxide production.

Pre- and postischemic effects of the NMDA receptor antagonist dizocilpine maleate (MK-801) on collateral cerebral blood flow.

The authors studied the effects of pre- and postischemic administration of dizocilpine maleate (MK-801) on collateral and regional cerebral blood flow (CBF). The ischemic penumbra appears to benefit most from the neuroprotective effects of MK-801. The precise mechanism by which MK-801 provides this neuroprotection remains controversial. Alterations in CBF have been demonstrated with MK-801 administration, but whether the response is an increase or decrease in flow has remained unclear. A left-sided craniectomy was performed in 20 dogs. A branch of the middle cerebral artery (MCA) was cannulated and collateral blood supply-dependent tissue (CDT) was identified using the "shadow flow" technique. Regional CBF was measured using radiolabeled microspheres. Six dogs received MK-801 (1 mg/kg administered intravenously) before they underwent MCA branch occlusion; the remaining 14 dogs received MK-801 after they underwent MCA occlusion. Cerebral blood flow and vascular pressures were measured 30 and 60 minutes after MK-801 administration. In animals that received MK-801 before MCA occlusion, CBF did not change significantly from baseline values before or after occlusion. In contrast, in animals that received MK-801 after MCA occlusion, CBF was significantly reduced in all regions of the brain, including the CDT. Collateral blood supply-dependent tissue showed a 51.7% reduction in flow, whereas normal CBF was reduced by 29.7%. The MK-801 induced cerebral vasoconstriction in both groups. The neuroprotective effects of MK-801 do not appear to be caused by the augmentation of collateral or global cerebral circulation and, in fact, may block the glutamate-mediated vasodilation that occurs during ischemia.

Quantitative Cerebral Blood Flow Determinations in Acute Ischemic Stroke

The advent of new modalities to treat acute ischemic stroke presents the need for accurate, early diagnosis. In acute ischemic stroke, CT scans are frequently normal or reveal only subtle hypodense changes. This study explored the utility and increased sensitivity of xenonenhanced CT (XeCT) in the diagnosis of acute cerebral ischemia and investigated the relationship between cerebral blood flow (CBF) measurements and early CT and angiographic findings in acute stroke. The CT scans, XeCT scans, and angiograms of 20 patients who presented within 6 hours of acute anterior circulation ischemic strokes were analyzed. CT scans were abnormal in 11 (55%) of 20 patients. XeCT scans were abnormal in all 20 (100%) patients, showing regions of interest with CBF < 20 (mL/100 g per minute) in the symptomatic middle cerebral artery (MCA) territories. The mean CBF in the symptomatic MCA territories was significantly lower than than of the asymptomatic MCA territories (P < .0005). In patients with basal ganglia hypodensities, the mean symptomatic MCA territory CBF was significantly lower than that of patients who did not exhibit these early CT findings (P < .05). The mean symptomatic MCA territory CBF in patients with angiographic M1 occlusions was significantly lower than that of patients whose infarcts were caused by MCA branch occlusions (P < .01). These results show that XeCT is more sensitive than CT in detecting acute strokes and that CBF measurements correlate with early CT and angiographic findings. XeCT may allow for the hyperacute identification of subsets of patients with acute ischemic events who are less likely to benefit and more likely to derive complications from aggressive stroke therapy.

Volume of Infarction and Blood Flow in Cerebral Embolism

The value of measuring asymmetry of cerebral perfusion semiquantitatively by single-photon emission computed tomography (SPECT) correlated with measuring the volume of infarction on computed tomography (CT) was evaluated in cerebral embolism. Eighteen patients with acute cerebral embolism (mean age: sixty-nine years) were evaluated. Ten were diagnosed as having middle cerebral artery (MCA) occlusion, 3 as having MCA branch occlusion, and 4 as having unilateral and 1 as having bilateral internal carotid occlusion. The infarct volume was measured, summing up the area of infarction on CT, at 8.5 days, mean time after onset. Outcomes of the patients were classified into three groups: good, fair, or dead, judged by the consequences one month after onset. Regional cerebral blood flow (rCBF) was measured in 9 of 10 surviving patients at one month, mean time after onset, by 123[iodine N-isopropyl-p-iodoamphetamine (IMP) SPECT. Semiquantitative rCBF index of asymmetry (AI) was evaluated from four regions of brain cortex. Eleven patients with < 300 mL infarct and 7 with > or = 300 mL infarct showed a significant difference of outcome with infarct volumes (P < 0.01). The mean AI value in patients with < 150 mL infarct was 31% while it was 52% with > or = 150 mL infarct (P < 0.039). There were significant linear correlations between mean AI values and the volumes of infarction or infarct/brain volume ratios (P < 0.034 or P < 0.018). The significant correlations of the AI values with the volumes of infarction suggest that the measured asymmetry of perfusion evaluated by SPECT could reflect the ultimate tissue damage and residual intact brain volume after cerebral embolism.

Color‐coded Ultrasound Diagnosis of Vascular Occlusion in Acute Ischemic Stroke

A combination of extracranial and transcranial color-coded sonography was used to identify the patterns of vascular occlusion in 47 patients with acute ischemic stroke. Total anterior circulation infarction (n = 20) was associated with internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion (n = 8 and 9, respectively), or with significant reduction in ipsilateral MCA velocities (n = 5). Patients with partial anterior circulation (n = 22) infarction had patency of the ipsilateral ICA and MCA. In this group, significant reduction of ipsilateral MCA velocities (n = 7) was associated with more extensive infarcts on conventional neuroimaging (n = 6), suggesting multiple MCA branch occlusions. Ultrasound imaging was unable to identify underlying vascular pathology in patients with posterior circulation infarction or with lacunar infarction (n = 5). An ultrasound-based approach enables noninvasive identification of major vascular pathology of the anterior cerebral circulation in patients with acute cerebral infarction. It may be useful for the rapid identification of patients most and those least likely to benefit from acute intervention, and for monitoring their response.

Embolic stroke after smoking "crack" cocaine.

A 39-year-old woman had an embolic upper division middle cerebral artery branch occlusion 3 hours after smoking the free base of cocaine ("crack"). Radionuclide ventriculography demonstrated cardiomyopathy, and echocardiography documented a left atrial thrombus. This case demonstrates that embolism is one mechanism of ischemic stroke after cocaine use, and that cardiomyopathy, possibly cocaine induced, may be the source of embolus. A cardiac source of embolus should be sought in patients with cocaine-associated cerebral infarction.