From the Departments of Radiology (P.R., L.T.R., M.P.F., D.P., W.G.K.) and Neuroradiology (F.D.), University Hospital, LMU Munich, Marchioninistr 15, 81377 Munich, Germany; Institute for Diagnostic and Interventional Radiology, University Medical Center Rostock, Rostock, Germany (K.M.T.); Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Canada (N.D.F., W.G.K.); and Department of Neuroradiology, University Hospital Schleswig-Holstein, Luebeck, Germany (A.K.).
Radiology. 2019 May;291(2):451-458. doi: 10.1148/radiol.2019182041. Epub 2019 Mar 19.
Background Recent studies have proven the effectiveness of thrombectomy up to 24 hours after stroke onset for patients with specific criteria at advanced CT or MRI. Clinical implementation of treatment in this extended time window remains a challenge, as many stroke centers do not routinely use advanced imaging. Purpose To determine whether automated cerebral x-ray attenuation measurements at noncontrast CT provide information on the presence of CT perfusion-defined ischemic core as applied in late time windows for thrombectomy. Materials and Methods In this retrospective study, patients with middle cerebral artery stroke due to proximal occlusion from 2009 to 2017 were included. All patients underwent noncontrast CT and CT perfusion. Automated software was used to calculate relative Hounsfield unit (rHU) values for Alberta Stroke Program Early CT Score (ASPECTS) regions on noncontrast CT images as the ratio of x-ray attenuation between ischemic versus non-ischemic hemispheres. Sensitivity, specificity, and diagnostic performance of rHU and composite rHU-ASPECTS, a score incorporating rHU from all regions, were analyzed for the classification of regional ischemic core and late time window thrombectomy criteria at CT perfusion. Results Data in a total of 200 patients were evaluated (105 women [mean age, 74 years ± 14 {standard deviation}] and 95 men [mean age, 76 years ± 14]). There were 121 patients in the validation cohort and 79 patients in the independent test cohort. Compared among all examined regions, rHU values yielded the best classification of ischemic core for the caudate nucleus, the lentiform nucleus, and the insula (with areas under the receiver operating characteristic curve [AUCs] ranging from 0.70 to 0.77; < .001 for each). The composite rHU-ASPECTS score allowed classification of CT perfusion imaging selection criteria of ischemic core sizes of less than 70 mL and target mismatch of greater than 1.8 with AUCs of 0.80 ( = .001; 75% sensitivity and 83% specificity) in the test cohort and 0.74 ( < .001; 58% sensitivity and 82% specificity) in the validation cohort. Conclusion Noncontrast CT x-ray attenuation measurements identify Alberta Stroke Program Early CT Score regions classified as ischemic core at CT perfusion. This approach may serve as a selection criteria surrogate for thrombectomy in late time windows. © RSNA, 2019
背景 最近的研究证明，对于符合特定标准的患者，在卒中发病后 24 小时内进行血栓切除术是有效的，这些患者接受了高级 CT 或 MRI 检查。由于许多卒中中心不常规使用高级影像学，因此在这个延长的时间窗内实施治疗仍然是一个挑战。目的 确定非增强 CT 上的自动脑 X 射线衰减测量是否可提供 CT 灌注定义的缺血核心存在的信息，这些信息适用于血栓切除术的晚期时间窗。材料与方法 在这项回顾性研究中，纳入了 2009 年至 2017 年间因近端闭塞导致大脑中动脉卒中的患者。所有患者均接受了非增强 CT 和 CT 灌注检查。使用自动软件计算非增强 CT 图像上的阿尔伯塔卒中项目早期 CT 评分（Alberta Stroke Program Early CT Score，ASPECTS）区域的相对 Hounsfield 单位（relative Hounsfield unit，rHU）值，该值为缺血半球与非缺血半球之间 X 射线衰减的比值。分析 rHU 和包含所有区域 rHU 的复合 rHU-ASPECTS（评分）对 CT 灌注时区域性缺血核心和晚期时间窗血栓切除术标准的分类的敏感性、特异性和诊断性能。结果 在总共 200 例患者中评估了数据（105 例女性[平均年龄，74 岁±14{标准差}岁]和 95 例男性[平均年龄，76 岁±14 岁]）。验证队列中有 121 例患者，独立测试队列中有 79 例患者。与所有检查区域相比，rHU 值对尾状核、豆状核和岛叶的缺血核心分类最佳（受试者工作特征曲线下面积[area under the receiver operating characteristic curve，AUC]范围为 0.70 至 0.77；每个区域均<0.001）。复合 rHU-ASPECTS 评分可对 CT 灌注成像选择缺血核心<70 mL 且靶失配>1.8 的标准进行分类，验证队列中的 AUC 为 0.80（<0.001；敏感性为 75%，特异性为 83%），测试队列中的 AUC 为 0.74（<0.001；敏感性为 58%，特异性为 82%）。结论 非增强 CT 射线衰减测量可识别 CT 灌注中被归类为缺血核心的 Alberta Stroke Program Early CT Score 区域。这种方法可能成为晚期时间窗内血栓切除术的选择标准替代指标。©RSNA，2019
