Chalela J A, Alsop D C, Gonzalez-Atavales J B, Maldjian J A, Kasner S E, Detre J A
Department of Neurology, University of Pennsylvania, Philadelphia 19104, USA.
Stroke. 2000 Mar;31(3):680-7. doi: 10.1161/01.str.31.3.680.
Continuous arterial spin-labeled perfusion MRI (CASL-PI) uses electromagnetically labeled arterial blood water as a diffusible tracer to noninvasively measure cerebral blood flow (CBF). We hypothesized that CASL-PI could detect perfusion deficits and perfusion/diffusion mismatches and predict outcome in acute ischemic stroke.
We studied 15 patients with acute ischemic stroke within 24 hours of symptom onset. With the use of a 6-minute imaging protocol, CASL-PI was measured at 1.5 T in 8-mm contiguous supratentorial slices with a 3.75-mm in-plane resolution. Diffusion-weighted images were also obtained. Visual inspection for perfusion deficits, perfusion/diffusion mismatches, and effects of delayed arterial transit was performed. CBF in predetermined vascular territories was quantified by transformation into Talairach space. Regional CBF values were correlated with National Institutes of Health Stroke Scale (NIHSS) score on admission and Rankin Scale (RS) score at 30 days.
Interpretable CASL-PI images were obtained in all patients. Perfusion deficits were consistent with symptoms and/or diffusion-weighted imaging abnormalities. Eleven patients had hypoperfusion, 3 had normal perfusion, and 1 had relative hyperperfusion. Perfusion/diffusion mismatches were present in 8 patients. Delayed arterial transit effect was present in 7 patients; serial imaging in 2 of them showed that the delayed arterial transit area did not succumb to infarction. CBF in the affected hemisphere correlated with NIHSS and RS scores (P=0.037 and P=0.003, Spearman rank correlation). The interhemispheric percent difference in middle cerebral artery CBF correlated with NIHSS and RS scores (P=0.007 and P=0.0002, respectively).
CASL-PI provides rapid noninvasive multislice imaging in acute ischemic stroke. It depicts perfusion deficits and perfusion/diffusion mismatches and quantifies regional CBF. CASL-PI CBF asymmetries correlate with severity and outcome. Delayed arterial transit effects may indicate collateral flow.
连续动脉自旋标记灌注磁共振成像（CASL-PI）利用电磁标记的动脉血中的水作为可扩散示踪剂，以无创方式测量脑血流量（CBF）。我们推测，CASL-PI能够检测灌注缺损和灌注/扩散不匹配情况，并预测急性缺血性卒中的预后。
我们研究了15例症状发作后24小时内的急性缺血性卒中患者。采用6分钟成像方案，在1.5T磁场下，对幕上连续8mm厚的层面进行CASL-PI测量，层面内分辨率为3.75mm。同时还获取了扩散加权图像。对灌注缺损、灌注/扩散不匹配以及动脉转运延迟的影响进行了视觉评估。通过转换到Talairach空间，对预定血管区域的CBF进行定量分析。将区域CBF值与入院时的美国国立卫生研究院卒中量表（NIHSS）评分以及30天时的改良Rankin量表（RS）评分进行相关性分析。
所有患者均获得了可解读的CASL-PI图像。灌注缺损与症状和/或扩散加权成像异常一致。11例患者存在灌注不足，3例灌注正常，1例存在相对高灌注。8例患者存在灌注/扩散不匹配。7例患者存在动脉转运延迟效应；其中2例的系列成像显示，动脉转运延迟区域未发生梗死。患侧半球的CBF与NIHSS和RS评分相关（P=0.037和P=0.003，Spearman等级相关性）。大脑中动脉CBF的半球间百分比差异与NIHSS和RS评分相关（分别为P=0.007和P=0.0002）。
CASL-PI可为急性缺血性卒中提供快速无创的多层成像。它能够描绘灌注缺损和灌注/扩散不匹配情况，并对区域CBF进行定量分析。CASL-PI的CBF不对称性与严重程度及预后相关。动脉转运延迟效应可能提示侧支循环。
