What constitutes a true hyperdense middle cerebral artery sign?
What constitutes a true hyperdense middle cerebral artery sign?
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DOI：
10.1159/000016101
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发表时间：
2000-11-01
影响因子：
2.9
通讯作者：
Muir, KW
中科院分区：
文献类型：
--
作者：
Koo, CK;Teasdale, E;Muir, KW
目的：“MCA高密度征”是指大脑中动脉（MCA）近端衰减增加的表现，通常与M1 MCA段血栓形成相关，可能是缺血性卒中后早期计算机断层扫描的唯一诊断特征。假阳性是可以识别的，因此，随着卒中溶栓治疗的出现，正确识别这种体征变得更加重要。我们试图确定MCA高密度的客观标准。方法：由一名观察者分析在神经放射科通过标准协议获得的脑计算机断层扫描图像。将所有报告为显示高密度MCA的连续扫描与报告为正常扫描的对照进行比较。将感兴趣的卵形区域放置在血管和大脑皮质上，并测量亨氏单位（HU）的衰减。比较两组的绝对衰减值和一侧与另一侧的比值。结果：病例组（n = 18）和对照组（n = 80）MCA衰减与年龄无关。与对照组相比，病例受累MCA的平均MCA衰减更大[54.0 HU（99%置信区间CI 46.7-61.2）vs. 41.3 HU（99% CI 39.7-43.0）; p < 0.00001]。根据MCA密度：密度较低的比率（在或不在对照的95%预测区间内），将病例细分为真阳性和假阳性。在所有真阳性中，MCA比率> 1.2。9/10例真阳性患者发生急性缺血性卒中; 1例患者发生单纯疱疹病毒性脑炎，但MCA衰减在对照组的95%CI内。假阳性有成熟的脑梗死或非缺血性病理。MCA衰减与邻近大脑皮质的比率在真阳性和假阳性中均显著高于对照组。结论：与急性缺血性中风相关的高密度MCA可以通过测量受累血管和正常血管的绝对衰减来与正常血管和假阳性区分开来：绝对密度>43 HU和MCA比率>1.2定义为高密度，并排除所有其他病理。需要在其他中心确认。版权所有（C）2000 S. Karger AG，巴塞尔。
Objectives: The 'hyperdense MCA sign' refers to an appearance of increased attenuation of the proximal middle cerebral artery (MCA) that is often associated with thrombosis of the M1 MCA segment a nd may be the only diagnostic feature on computed tomography early after ischaemic stroke. False positives are recognized, and correct recognition of this sign has, therefore, assumed greater importance with the advent of thrombolytic therapy for stroke. We sought to define objective criteria for hyperdensity of the MCA. Methods: Brain computed tomographs obtained by a standard protocol in a neuroradiology department were analyzed by a single observer. All consecutive scans reported as exhibiting a hyperdense MCA were compared to controls reported as having normal scans. Ovoid regions of interest were placed over the vessels and cerebral cortices, and the attenuation in Hounsfield units (HU) measured. Absolute attenuation and ratios of one side to the other were compared. Results: MCA attenuation was unrelated to age in cases (n = 18) and controls (n = 80). The mean MCA attenuation was greater in the affected MCA of cases as compared with controls [54.0 HU (99% confidence interval CI 46.7-61.2) vs. 41.3 HU (99% CI 39.7-43.0); p < 0.00001]. Cases were subdivided into true and false positives by the ratio of denser:less dense MCA (within or without the 95% prediction interval for controls). In all true positives, the MCA ratio was > 1.2. 9 of 10 true positives had acute ischaemic stroke; 1 patient had herpes simplex encephalitis, but had MCA attenuation within the 95% CI for controls. False positives had mature cerebral infarction or non-ischaemic pathologies. The ratio of MCA attenuation to adjacent cerebral cortex was significantly higher in both true and false positives than in controls. Conclusions: Hyperdense MCAs associated with acute ischaemic stroke can be distinguished from normal vessels and false positives by measurement of absolute attenuation of affected and normal vessels: an absolute density of >43 HU and a MCA ratio of >1.2 defined hyperdensity and excluded all other pathologies. Confirmation in other centres is required. Copyright (C) 2000 S. Karger AG, Basel.