Portion Of Anterior Cerebral Artery Research Articles

Pencil Beam Presaturation Magnetic Resonance Imaging Helps to Identify Patients at Risk for Intolerance to Temporary Internal Carotid Artery Occlusion During Carotid Endarterectomy and Carotid Artery Stenting

There has been no effective method to predict ischemic intolerance to temporary internal carotid artery (ICA) occlusion during carotid artery reconstruction. Pencil beam presaturation (BeamSAT) pulse suppresses the flow signal of the target vessel in magnetic resonance angiography (MRA). Applying this method, we constructed ICA-selective MRA images. The aim of this study was to identify patients at risk for ischemic intolerance by ICA-selective MRA. By evaluating flow of anterior communicating artery (Acom) and A1 portion of anterior cerebral artery with ICA-selective MRA and posterior communicating artery (Pcom) with conventional MRA, we investigated associations of these collateral flow patterns with ischemic intolerance and decrease of regional cerebral oxygen saturation. The study included 58 patients who underwent carotid endarterectomy or carotid artery stenting. Six of 7 patients without Acom flow and Pcom flow demonstrated ischemic intolerance, whereas all patients (n= 51) with Acom and/or Pcom flow demonstrated tolerance. The accuracy of this prediction model according to Acom and Pcom flow patterns for ischemic intolerance was 0.98 (P=0.01, binomial test). Regional cerebral oxygen saturation decrease after ICA occlusion was significantly larger in patients without Acom flow and Pcom flow (12.0%± 6.0%) than in patients with Acom flow and Pcom flow (3.0% ± 3.1%, P < 0.01) and in patients with Acom flow but no Pcom flow (2.4% ± 5.2%, P < 0.01). These findings support the importance of Acom flow as a collateral route. ICA-selective MRA enables prediction of ischemic intolerance to temporary ICA occlusion during carotid endarterectomy or carotid artery stenting. This method provides valuable information regarding probability of an ischemic complication.

The Impact of Absent A1 Segment on Ischemic Stroke Characteristics and Outcomes

A1 segment is the proximal portion of anterior cerebral artery. Absence of the A1 segment can compromise anterior cerebral collateral blood flow. Few studies have examined the association of an absent A1 segment and ischemic stroke outcome. We sought to determine the association between A1 absence and affected vessel territory, stroke volume, and outcomes among patients with acute ischemic stroke (AIS). A retrospective review of prospectively identified patients with AIS from July 2008 to March 2013 was performed. Patients without intracranial vascular imaging were excluded. We compared patients with absent A1 to patients with bilateral A1 segments in terms of demographics, stroke severity (as measured by National Institute of Health Stroke Scale [NIHSS]), vascular distribution, and in-hospital mortality using the chi-square test and logistic regression. Of the 1146 patients with AIS and intracranial vascular imaging, 5.9% patients (n = 68) had absent A1. Compared with other AIS patients, those with absent A1 were older (65 vs. 63 years old, respectively, P = .016). There was no difference between groups in terms of the vascular distribution or the side of the stroke. The median volume of the infracted tissue was similar across the groups even when it was stratified according to the Treatment of Acute Stroke Trial classification. Patients with an absent A1 had twice higher odds of in-hospital mortality (odds ratio, 2.4; 95% confidence interval, 1.1-5.2; P = .028); however, significance was lost after adjusting to age, NIHSS at baseline, and glucose on admission. Other outcome measures were similar across the groups. In our sample, patients with an absent A1 segment did not have a specific vascular distribution, larger infarct volume, or worse outcomes.

Diagnosis and Treatment of Moyamoya Disease

Moyamoya disease is a cerebrovascular disease of unknown etiology, which is characterized by bilateral stenosis or occlusion at terminal portion of internal carotid artery and at proximal portion of anterior cerebral artery and /or middle cerebral artery and abnormal vascular network in the vicinity of the arterial occlusions. It occurs frequently in Asian countries, particularly in Korea and Japan, but is rare in Western countries. To establish the etiology of moyamoya disease, much about the pathology from autopsies, factors involved in its pathogenesis, and its genetics have been studied. It may occur at any age from childhood to adulthood and in general, initial manifestation is cerebral ischemic symptoms in children and intracranial hemorrhage symptoms in adults. Because it progress and cause recurrent stroke, early diagnosis and proper management has been recognized. Cerebral angiography is essential for definitive diagnosis and treatment plan. Magnetic resonance imaging/magnetic resonance angiography is useful for diagnosis and follow-up tools after revascularization. Evaluation of the cerebral hemodynamics by single photon emission computed tomography and positron emission tomography is useful for diagnosis and assessment of the severity of cerebral ischemia in moyamoya patients. Surgical revascularization is effective for moyamoya disease manifesting as ischemic symptoms, to prevent further ischemia and infarction. In hemorrhagic type moyamoya disease, revascularization can be considered. Direct bypass, indirect synangiosis and combined methods are used. Outcomes of revascularization are excellent in preventing transient ischemic attacks in most patients. (Ewha Med J 2013;36(1):9-17)