Objective To evaluate a standardised (s)toke window'in non-enhanced computed tomography (NECT)of the brain in the diagnosis of early ischemic changes (EIC).Methods Retrospective analysis was performed using clinical data from 168 patients who had been diagnosed with EIC by MRI or DSA within the first 360 minutes of an onset.Two resident physicians of the Radiology Department used the default window (100 HU,35 HU) and a (s)toke window'(30 HU,35 HU) to assess EIC and its various signs every other two weeks.The final confirmation by two attending physicians was set as the gold standard.The diagnostic accuracy of the two windows was compared.Results A total of 113 patients (67.3％) were confirmed with EIC signs,including 59 patients with hyperdense middle cerebral artery sign (HMCAS),5 with hyperdense posterior cerebral artery sign (HPCAS),42 with disappearing basal ganglia sign,35 with loss of the insular ribbon sign,29 with cortical sulcal effacement sign and 31 with focal hypodensity sign.The resident physicians detected 72 EIC cases (42.9％) using the default window,which was remarkably reduced compared with "the gold standards" (P ＜ 0.01).In contrast,107 cases (63.7％) were detected when the "stroke window" was applied,which was not statistical different from the results by the gold standards (P ＞ 0.05).Comparing with the default window,marked more EIC cases were found using the "stroke window" (P ＜ 0.01).Except for the HPCAS,the detection rate by the default window based on other EIC signs were substantially decreased compared with the "gold standard"(P ＜ 0.05).No statistical difference was found through fewer signs were detected by the residents using the (s)troke window'than the "gold standard" (P ＞ 0.05).Remarkable more signs were detected by the residents using the (s)troke window'compared with the default window (P ＜ 0.05).Conclusions "Stroke window" observation can significantly facilitate the residents to improve their detection rate of EIC.%目的 通过头颅非增强CT(NECT)标准化“卒中窗”设置,评估其对早期缺血改变(EIC)的诊断价值.方法 回顾性分析168例在症状发作的360 min内检查并经MRI或DSA确认EIC的患者.2名放射科住院医师间隔2周先后使用默认窗宽窗位(100 HU、35 HU)、“卒中窗”(30 HU、35 HU)评估EIC及其各种征象,以2名主治医师的最终确认为“金标准”,分别比较住院医师使用默认窗和“卒中窗”对EIC征象的诊断准确率.结果 最终确认存在各种EIC征象的患者有113例(67.3％),其中,大脑中动脉高密度征59例,大脑后动脉高密度征5例,基底节轮廓消失征42例,脑岛带消失征35例,皮质脑沟变浅征29例,局灶性低密度征31例.住院医师使用默认窗仅发现72例(42.9％)EIC,显著少于“金标准”(P＜0.01);但使用“卒中窗”检测到EIC 107例(63.7％),与“金标准”的差异有统计学意义(P＞0.05);住院医师使用“卒中窗”检测到EIC显著高于默认窗(P＜0.01).除了大脑后动脉高密度征,在EIC的其他各种征象方面,住院医师使用默认窗EIC检出率均显著少于“金标准”(P＜0.05);尽管使用“卒中窗”检测到EIC的征象少于“金标准”,但差异均无统计学意义(P＞0.05);住院医师使用“卒中窗”检测到EIC的征象显著高于默认窗(P＜0.05).结论 通过“卒中窗”观察可以显著提高住院医师对EIC的发现率.
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