医学影像学杂志

目的 探讨低剂量CT灌注成像联合低浓度对比剂对急性缺血性脑卒中的诊断价值。方法 选取84例急性缺血性脑卒中患者，随机分为低剂量组（42例）和常规剂量组（42例）。低剂量组采用70 kV管电压、管电流量150 mAs及低浓度对比剂（320 mgI/mL），常规剂量组采用120 kV管电压、固定管电流量（250 mAs）及370 mgI/mL对比剂。比较两组CT剂量指数（CTDIvol）、剂量长度乘积（DLP）、有效剂量（ED）及灌注参数[脑血流量（CBF）、脑血容量（CBV）、平均通过时间（MTT）、达峰时间（TTP）]。采用受试者工作特征（ROC）曲线评估低剂量CT灌注成像联合低浓度对比剂对急性缺血性脑卒中的诊断效能。结果 低剂量组CTDIvol、DLP及有效剂量分别降低61.8%、53.6%和58.2%(t分别为74.95、37.15、44.24,P均<0.001)。ROC曲线分析显示，各灌注参数均有较好的诊断效能，TTP的诊断效能最佳，曲线下面积为0.860(95%CI:0.774～0.947);MTT次之，曲线下面积为0.853(95%CI:0.765～0.941);CBF和CBV的曲线下面积分别为0.811(95%CI:0.705～0.917)和0.810(95%CI:0.703～0.916)。结论 低剂量CT灌注成像联合低浓度对比剂对急性缺血性脑卒中的诊断效能较高，且能显著降低辐射剂量。

Objective To investigate the application value and optimization strategy of low-dose CT perfusion imaging combined with low-concentration contrast agent in the diagnosis of acute cerebral infarction. Methods 84 patients with acute cerebral infarction were selected. Patients were randomly divided into low-dose group(n=42) and conventional-dose group(n=42).The low-dose group was adopted 70 kV tube voltage, 150 mAs tube current, and low-concentration contrast agent(320 mgI/mL); the conventional-dose group was used 120 kV tube voltage, 250 mAs tube current, and 370 mgI/mL contrast agent. CT dose index(CTDIvol), dose length product(DLP), effective dose, and perfusion parameters, such as cerebral blood flow(CBF), cerebral blood volume(CBV), mean transit time(MTT), time to peak(TTP), were compared between the two groups. ROC curve analysis was used to evaluate the diagnostic efficiency of the low-dose protocol. Results The CTDIvol, DLP, and effective dose in the low-dose group were reduced by 61.8%, 53.6%, and 58.2%, respectively(t=74.95, 37.15, 44.24, all P<0.001).ROC curve analysis showed that TTP had the best diagnostic performance with AUC of 0.860(95%CI: 0.774-0.947), followed by MTT with AUC of 0.853(95%CI: 0.765-0.941). AUC values for CBF and CBV were 0.811(95%CI: 0.705-0.917) and 0.810(95%CI: 0.703-0.916), respectively. Conclusion Low-dose CT perfusion imaging combined with low-concentration contrast agent maintains reliable diagnostic efficiency, while significantly reducing radiation dose, thereby making it a viable optimization protocol for diagnosing acute cerebral infarction.