计算机断层扫描灌注成像对aSAH后早期延迟性脑缺血的诊断价值

Diagnostic value of CT perfusion imaging for early delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

目的评估计算机断层扫描灌注成像(CTP)对动脉瘤性蛛网膜下腔出血(a SAH)后早期延迟性脑缺血(DCI)的诊断价值。方法对59例a SAH患者早期(4~6d)进行CTP检查,推导各灌注参数诊断DCI的最佳阈值。术后随访2个月,根据DCI诊断标准分为DCI组(21例)和无DCI组(38例),比较两组患者的临床资料。结果 DCI发生率为35.6%(21/59)。两组患者在性别、年龄、BMI、合并症、改良版世界神经外科联盟分级量表(WFNS分级)、Fisher分级、肿瘤位置、肿瘤直径、手术方式等方面比较,差异均无统计学意义(均P>0.05);在灌注参数绝对值方面,DCI组较无DCI组的CBF、CBV均明显降低(均P<0.05),MTT、TTP均明显延长(均P<0.01);在CBV比值、CBF比值、MTT差值、TTP差值等灌注参数比较,两组差异亦均有统计学意义(均P<0.05)。除CBV外,CBF、MTT、TTP、CBV比值、CBF比值、MTT差值、TTP差值的AUC>0.75,最佳阈值分别为17.22ml/(100g·min)、9.50s、11.48s、0.88、0.86、0.68s、1.31s;其中CBF比值、MTT差值的AUC较高,其灵敏度分别为0.79、0.71,特异度分别为0.81、0.67。结论 CTP能提供脑血流动力学证据,对a SAH后早期(4~6d)DCI具有诊断价值。除CBV外,其余灌注参数均有良好的诊断准确性;其中CBF比值、MTT差值诊断DCI的价值最好。

Objective To evaluate the application of computed tomography perfusion imaging（CTP） in diagnosis of early delayed cerebral ischemia（DCI） after aneurysmal subarachnoid hemorrhage（a SAH）. Methods Fifty nine patients with a SAH underwent CTP examination 4-6 days after the onset, and the optimal threshold values of DCI were deduced for each perfusion parameter. During the 2 month-follow-up DCI occurred in 21 patients（DCI group） with an incidence rate of 35.6%, and did not occur in rest 38 patients（non-DCI group）. The clinical data were compared between the two groups. Results There were no statistically significant differences in gender, age, BMI, comorbidities, modified World Federation of Neurosurgical Societies Classification（WFNS classification）, Fisher classification, location and diameter of aneurysm, and surgical methods between the two groups（P〈0.05）. In absolute values of perfusion parameters, CBF and CBV in DCI group were significantly lower and MTT and TTP were significantly prolonged than those in DCI group（all P〈0.05）. Differences in perfusion parameters such as CBV ratio, CBF ratio, MTT difference, and TTP difference were also statistically significant（all P〈0.05）. The areas under the ROC curve（AUCs） of the ratios of CBF, MTT, TTP, CBV, CBF, MTT difference, and TTP difference all were0.75, and the optimal thresholds were 17.22 ml/（100 g·min）, 9.50 s, 11.48 s, 0.88, 0.86, 0.68 s and 1.31 s respectively. Among them, the AUC of CBF ratio and M TT difference were the highest with the sensitivity was 0.79, 0.71 and the specificity was 0.81 and 0.67 respectively.Conclusion CTP provides evidence of cerebral hemodynamics and may be used for diagnosis of early DCI after a SAH, particularly with CTP parameters CBF ratio and MTT difference.