Section on Stroke Diagnostics and Therapeutics, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1063, USA.
Stroke. 2012 Mar;43(3):753-8. doi: 10.1161/STROKEAHA.111.635979. Epub 2012 Feb 16.
The aim of this study was to test whether arterial spin labeling (ASL) can detect significant differences in relative cerebral blood flow (rCBF) in the core, mismatch, and reverse-mismatch regions, and whether rCBF values measured by ASL in those areas differ from values obtained using dynamic susceptibility contrast (DSC) MRI.
Acute stroke patients were imaged with diffusion-weighted imaging (DWI) and perfusion-weighted imaging (ASL and DSC) MRI. An expert reader segmented the ischemic lesion on DWI and the DSC time-to-peak (TTP) maps. Three regions were defined: core (DWI+, TTP+), mismatch (DWI-, TTP+), and reverse-mismatch (DWI+, TTP-). For both ASL and DSC, rCBF maps were created with commercially available software, and the ratio was calculated as the mean signal intensity measured on the side of the lesion to that of the homologous region in the contralateral hemisphere. Values obtained from core, mismatch, and reverse-mismatch were used for paired comparison.
Twenty-eight patients were included in the study. The mean age was 65.6 (16.9) years, with a median baseline National Institutes of Health Stroke Scale score of 10 (interquartile range, 4-17). Median time from last known normal to MRI was 5.7 hours (interquartile range, 2.9-22.6). Mean rCBF ratios were significantly higher in the mismatch 0.53 (0.23) versus the core 0.39 (0.33) and reverse-mismatch 0.68 (0.49) versus the core 0.38 (0.35). Differences in rCBF measured with DSC and ASL were not significant.
ASL allows for the measurement of rCBF in the core and mismatch regions. Values in the mismatch were significantly higher than in the core, suggesting there is potential salvageable tissue.
本研究旨在测试动脉自旋标记（ASL）是否可检测到核心、不匹配和反向不匹配区域相对脑血流（rCBF）的显著差异，以及 ASL 在这些区域测量的 rCBF 值是否与动态对比磁共振成像（DSC MRI）获得的值不同。
对急性脑卒中患者进行弥散加权成像（DWI）和灌注加权成像（ASL 和 DSC）MRI 检查。一位专家读者对 DWI 上的缺血性病变和 DSC 时间至峰值（TTP）图进行了分割。定义了三个区域：核心（DWI+，TTP+）、不匹配（DWI-，TTP+）和反向不匹配（DWI+，TTP-）。对于 ASL 和 DSC，使用商业可用软件创建 rCBF 图，并计算病变侧与对侧半球同源区域之间测量的平均信号强度的比值。使用核心、不匹配和反向不匹配获得的值进行配对比较。
本研究共纳入 28 例患者。患者的平均年龄为 65.6（16.9）岁，基线国立卫生研究院卒中量表评分中位数为 10（四分位距，4-17）。从最后一次正常到 MRI 的中位时间为 5.7 小时（四分位距，2.9-22.6）。不匹配时 rCBF 比值 0.53（0.23）显著高于核心时 rCBF 比值 0.39（0.33），反向不匹配时 rCBF 比值 0.68（0.49）显著高于核心时 rCBF 比值 0.38（0.35）。DSC 和 ASL 测量的 rCBF 差异无统计学意义。
ASL 可测量核心和不匹配区域的 rCBF。不匹配区域的值明显高于核心区域，提示存在潜在的可挽救组织。
