Shih Ludy C, Saver Jeffrey L, Alger Jeffry R, Starkman Sidney, Leary Megan C, Vinuela Fernando, Duckwiler Gary, Gobin Y Pierre, Jahan Reza, Villablanca J Pablo, Vespa Paul M, Kidwell Chelsea S
UCLA Stroke Center, UCLA Medical Center, Los Angeles, Calif, USA.
Stroke. 2003 Jun;34(6):1425-30. doi: 10.1161/01.STR.0000072998.70087.E9. Epub 2003 May 8.
Identifying core, irreversibly infarcted tissue and salvageable penumbral tissue is crucial to informed, physiologically guided decision making regarding thrombolytic and other interventional therapies in acute ischemic stroke. Pretreatment perfusion MRI offers promise as a means to differentiate core from penumbral tissues.
Diffusion-perfusion MRIs were performed before treatment and on day 7 in patients undergoing successful vessel recanalization with intra-arterial thrombolytic therapy. Perfusion maps of the time to peak of the residue function (Tmax) were generated after deconvolution of an arterial input function. Initial perfusion abnormalities and final infarct regions were outlined by hand. Posttreatment images were coregistered to the pretreatment study. Voxel-by-voxel and volume analyses were performed to identify thresholds of perfusion abnormalities that best predict core, irreversibly infarcted tissue.
Fourteen patients (4 men, 10 women) with vessel recanalization were studied. Mean age was 73 years, and median entry National Institutes of Health Stroke Scale score was 12. Mean time from symptom onset to start of intra-arterial infusion was 245 minutes and to recanalization was 338 minutes. With a voxel-by-voxel analysis, Tmax > or =6 and > or =8 seconds (sensitivity, 71% and 53%; specificity, 63% and 80%) correlated most highly with day 7 final infarct. With a volume analysis, Tmax > or =6 and > or =8 seconds (r2=0.704 and r2=0.705) correlated most highly with day 7 final infarct.
Perfusion-weighted imaging measures of ischemia severity accurately differentiate irreversibly injured core from penumbral, salvageable tissue. The best threshold for identifying core infarcted tissue is adjusted Tmax of > or =6 to 8 seconds.
识别核心的、不可逆梗死组织和可挽救的半暗带组织，对于在急性缺血性卒中中做出明智的、基于生理指导的溶栓及其他介入治疗决策至关重要。治疗前灌注磁共振成像有望成为区分核心组织与半暗带组织的一种方法。
对接受动脉内溶栓治疗且血管成功再通的患者，在治疗前及治疗后第7天进行弥散灌注磁共振成像。通过对动脉输入函数进行去卷积，生成残余函数达峰时间（Tmax）的灌注图。手动勾勒出初始灌注异常区域和最终梗死区域。将治疗后的图像与治疗前的研究进行配准。进行逐像素和体积分析，以确定最能预测核心不可逆梗死组织的灌注异常阈值。
对14例血管再通患者（4例男性，10例女性）进行了研究。平均年龄为73岁，入院时美国国立卫生研究院卒中量表评分中位数为12分。从症状发作到开始动脉内输注的平均时间为245分钟，到血管再通的平均时间为338分钟。逐像素分析显示，Tmax≥6秒和≥8秒（敏感性分别为71%和53%；特异性分别为63%和80%）与第7天的最终梗死最相关。体积分析显示，Tmax≥6秒和≥8秒（r2分别为0.704和0.705）与第7天的最终梗死最相关。
灌注加权成像测量的缺血严重程度可准确区分不可逆损伤的核心组织与可挽救的半暗带组织。识别核心梗死组织的最佳阈值是调整后的Tmax≥6至8秒。
