Buch Karen, Hakimelahi Reza, Locascio Joseph J, Bolar Divya S, Gonzalez R Giliberto, Schaefer Pamela W
Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, Gray 241 G, Boston, MA, 02114, USA.
Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Neuroradiology. 2022 May;64(5):925-934. doi: 10.1007/s00234-021-02835-3. Epub 2021 Oct 18.
To assess the utility of ASL in evaluating patients presenting to the ED with stroke-like symptoms.
ASL and DWI images from 526 consecutive patients presenting to the ED with acute stroke symptoms were retrospectively reviewed. DWI images were evaluated for volume of restricted diffusion using ABC/2. ASL maps were evaluated for decreased, normal, or increased signal. The volume of decreased ASL signal was calculated using the same ABC/2 technique. The volume of decreased ASL signal was correlated with the volume of DWI signal abnormality to identify cases of mismatch (DWI:ASL ratio > 1.8) and to correlate this mismatch with infarct growth on imaging follow-up. NIHSS, length of hospital stay, mRS, and future admission for acute stroke-like symptoms were recorded. Correlations between ASL abnormalities and clinical parameters were evaluated using a two-tailed t-test.
Of the 526 patients presenting with acute stroke symptoms, 136 patients had an abnormal ASL scan and 388 patients had a normal ASL scan. Of the 136 patients with abnormal ASL, 84 patients had low ASL signal with 79 of these being related to acute infarcts. Elevated ASL signal was seen in 52 patients, of which 30 of these patients had reperfusion hyperemia related to acute infarctions. ASL had a negative predictive value of 94% for evaluating patients with acute ischemic stroke. A subset of patients with abnormal ASL scans with a discharge diagnosis of acute infarction were found to have an ASL:DWI mismatch (ratio > 1.8) and demonstrated significant lesion growth on follow-up imaging (57%). This included some patients who exhibited low ASL signal before development of diffusion restriction (infarction).
In patients presenting to the ED with acute stroke symptoms, ASL provides information not available with DWI alone. The NPV of ASL for evaluating patients with acute ischemia was 94%.
评估动脉自旋标记（ASL）在评估因类似中风症状就诊于急诊科的患者中的应用价值。
回顾性分析526例因急性中风症状就诊于急诊科的连续患者的ASL和扩散加权成像（DWI）图像。使用ABC/2法评估DWI图像上的扩散受限体积。评估ASL图上信号降低、正常或升高情况。使用相同的ABC/2技术计算ASL信号降低的体积。将ASL信号降低的体积与DWI信号异常的体积相关联，以识别不匹配病例（DWI:ASL比值>1.8），并将这种不匹配与影像学随访中的梗死灶生长相关联。记录美国国立卫生研究院卒中量表（NIHSS）评分、住院时间、改良Rankin量表（mRS）评分以及未来因急性类似中风症状的入院情况。使用双尾t检验评估ASL异常与临床参数之间的相关性。
在526例出现急性中风症状的患者中，136例患者ASL扫描异常，388例患者ASL扫描正常。在136例ASL异常的患者中，84例患者ASL信号低，其中79例与急性梗死有关。52例患者ASL信号升高，其中30例患者与急性梗死相关的再灌注充血有关。ASL在评估急性缺血性中风患者时的阴性预测值为94%。一部分出院诊断为急性梗死的ASL扫描异常患者被发现存在ASL:DWI不匹配（比值>1.8），并且在随访影像学检查中显示出明显的病灶生长（57%）。这包括一些在扩散受限（梗死）出现之前表现出低ASL信号的患者。
对于因急性中风症状就诊于急诊科的患者，ASL提供了单独DWI无法获得的信息。ASL评估急性缺血患者的阴性预测值为94%。
