van der Grond J, Balm R, Kappelle L J, Eikelboom B C, Mali W P
Department of Radiology, University Hospital Utrecht, Netherlands.
Stroke. 1995 May;26(5):822-8. doi: 10.1161/01.str.26.5.822.
Occlusion or severe stenosis of extracranial vessels may lead to hypoperfusion without overt infarction of brain tissue. The aim of this study was to investigate whether occlusion of the internal carotid artery or stenosis with reduction in diameter of more than 70% leads to altered cerebral metabolism in regions in which no infarcts are visible with magnetic resonance imaging.
We studied 10 control subjects and 55 patients with transient or nondisabling cerebral ischemia (25 patients with severe unilateral stenosis, 15 patients with unilateral occlusion, and 15 patients with bilateral severe stenosis or occlusion of the internal carotid artery). All subjects underwent magnetic resonance imaging and 1H magnetic resonance spectroscopic imaging. Cerebral metabolism was studied by assessing ratios of N-acetyl aspartate (NAA) to choline and to creatine as well as lactate from noninfarcted frontal, mesial, and parietal regions in the centrum semiovale in both hemispheres.
All patients with unilateral stenosis or occlusion of the internal carotid artery had decreased NAA/choline ratios in noninfarcted areas in the hemisphere on the side of the stenosis or occlusion and normal NAA/choline ratios in the contralateral hemisphere. Patients with bilateral stenosis or occlusion had decreased NAA/choline ratios in both hemispheres. In one third of all patients, cerebral lactate was found in regions without abnormalities on magnetic resonance imaging.
A severe reduction in the diameter of the internal carotid artery affects cerebral metabolism in regions that are not infarcted. These changes are reflected in a decreased NAA/choline ratio and a high incidence of cerebral lactate. These regions are probably at risk for infarction in the long term or if cerebral perfusion decreases further.
颅外血管闭塞或严重狭窄可能导致脑灌注不足，但脑组织无明显梗死。本研究旨在探讨颈内动脉闭塞或直径缩小超过70%的狭窄是否会导致磁共振成像未见梗死区域的脑代谢改变。
我们研究了10名对照受试者和55例短暂性或非致残性脑缺血患者（25例严重单侧狭窄患者、15例单侧闭塞患者以及15例双侧颈内动脉严重狭窄或闭塞患者）。所有受试者均接受了磁共振成像和1H磁共振波谱成像检查。通过评估双侧半卵圆中心非梗死额叶、内侧和顶叶区域中N - 乙酰天门冬氨酸（NAA）与胆碱、肌酸的比值以及乳酸水平来研究脑代谢。
所有单侧颈内动脉狭窄或闭塞患者狭窄或闭塞侧半球非梗死区域的NAA/胆碱比值降低，对侧半球NAA/胆碱比值正常。双侧狭窄或闭塞患者双侧半球的NAA/胆碱比值均降低。在所有患者的三分之一中，磁共振成像未见异常的区域发现了脑乳酸。
颈内动脉直径严重减小会影响未梗死区域的脑代谢。这些变化表现为NAA/胆碱比值降低以及脑乳酸的高发生率。这些区域长期来看或在脑灌注进一步降低时可能有梗死风险。
