Introduction Tissue at risk, as estimated by CT perfusion utilizing Tmax+6, correlates with final infarct volume (FIV) in acute ischemic stroke (AIS) without reperfusion. Tmax thresholds are derived from Western ethnic populations but not from ethnic Asian populations. We aimed to investigate the influence of ethnicity on Tmax thresholds. Methods From a clinical-imaging registry of Australian and Indonesian stroke patients, we selected a participant subgroup with the following inclusion criteria: AIS under 24 hours and absence of reperfusion therapy. Clinical data included demographics, time metrics, stroke severity, premorbid, and 3-month Modified Rankin Score. Baseline CTP and MRI <72 hours were performed. Volumes of Tmax utilizing different thresholds and final infarct volumes (FIV) were calculated. Spearman correlation was used to evaluate relationship involving ordinal variables and calculate the optimal Tmax threshold against FIV in both populations. Results Two hundred patients were included in the study sample 100 in Jakarta and 100 in Geelong. The median National Institutes Health Stroke Scale (IQR) were 6(3-11) and 3(1-5), respectively. The median Tmax+6(IQR) was 0 (0-46.5) in Jakarta group and 0(0-7.5) in Geelong group. The median FIV(IQR) was 0 (0-30.5) and 0 (0-5.5). Tmax +8s in Jakarta population against FIV showed Spearman's coefficient =0.72, representing the optimal Tmax threshold. Tmax+6s showed Spearman's coefficient =0.51 against FIV in the Geelong population. Conclusions Tmax thresholds approximating FIV were possibly different in the Asian when compared with the non-Asian populations. Future studies are required to extend and confirm the validity of our findings.

中文翻译：

---

种族对急性缺血性中风 CT 灌注参数阈值的可能影响。

简介 利用 Tmax+6 通过 CT 灌注估计的危险组织与无再灌注的急性缺血性卒中 (AIS) 中的最终梗塞体积 (FIV) 相关。Tmax 阈值源自西方种族人群，而非亚洲种族人群。我们的目的是调查种族对 Tmax 阈值的影响。方法 从澳大利亚和印度尼西亚中风患者的临床影像登记中，我们选择了一个符合以下纳入标准的参与者亚组：AIS 低于 24 小时且未接受再灌注治疗。临床数据包括人口统计、时间指标、中风严重程度、病前情况和 3 个月修正Rankin 评分。进行基线 CTP 和 MRI <72 小时。计算利用不同阈值的 Tmax 体积和最终梗塞体积 (FIV)。Spearman 相关性用于评估涉及顺序变量的关系，并计算两个群体中针对 FIV 的最佳 Tmax 阈值。结果 研究样本中包括 200 名患者，其中 100 名患者在雅加达，100 名患者在吉朗。美国国立卫生研究院健康中风量表 (IQR) 中位数分别为 6(3-11) 和 3(1-5)。雅加达组中位Tmax+6(IQR)为0(0-46.5)，吉朗组为0(0-7.5)。中位 FIV(IQR) 为 0 (0-30.5) 和 0 (0-5.5)。雅加达人群针对 FIV 的 Tmax +8s 显示斯皮尔曼系数 =0.72，代表最佳 Tmax 阈值。Tmax+6s 显示吉朗人群中针对 FIV 的 Spearman 系数 =0.51。结论 与非亚洲人群相比，亚洲人群接近 FIV 的 Tmax 阈值可能不同。未来的研究需要扩展并确认我们研究结果的有效性。