The Clinical Value Of Whole Brain CTP And Dynamic CTA Derived From CTP Data In Patients With Aneurysmal Subarachnoid Hemorrhage

Objective: To investigate the feasibility and clinical value of computed tomography perfusion(CTP)and dynamic computed tomography angiography(CTA)for cerebrovascular disease.Methods: Eighty patients were randomly divided into the perfusion group(n = 40)and the routine group(n = 40).Two radiologists evaluated the image quality of CTA.Objective evaluation includes: degree of arterial enhancement,detection rate of aneurysm,subjective evaluation including image quality,arteriole detail display ability,image noise and venous pollution.Meanwhile,analysed perfusion maps of CTP and dynamic CTA.Results: The artery enhancement value(P<0.001)and image noise(P<0.05)in the perfusion group were significantly higher than the routine group.But there were no significant differences(P>0.05)between the two groups in signal to noise ratio(SNR)and contrast to noise ratio(CNR).The differences of image quality,small arterial detail visibility and venous contamination were not statistically significant(P>0.05).There was no significant difference between the two groups for the diagnosis of aneurysm(P>0.05).Local perfusion decreased area were observed in 21 patients.Conclusion:1.Dynamic CTA images derived from whole brain CTP date have comparable image quality with routine CTA.In addition,it provides functional information of hemodynamics in whole brain perfusion.Objective: To investigate the value of whole-brain CT perfusion(CTP)and derived CT angiography(CTA)on admission to predict delayed cerebral ischemia(DCI)in patients with aneurysmal subarachnoid hemorrhage(a SAH).Methods: All patients received the one-stop whole-brain CTP scan within 24 hours after the aneurysm ruptured.CTP qualitative analysis according to the manifestation of perfusion maps,divided into three groups: 1)normal perfusion map,2)local hypoperfusion and 3)diffused hypoperfusion.The quantitative parameter values were divided into mean CTP and lowest CTP parameter value.The mean CTP parameter value was measured by measuring the CBF,CBV,MTT,TTD,TTS and TMax values of each patient in more than one place.The lowest CTP parameter value was measured by measuring the minimum value of CBF,CBV and the maximum value of MTT,TTD,TTS and Tmax were recorded only in each patient.Dynamic CTA was used to evaluate the occurrence of cerebral vasospasm(CVS)and the location of aneurysm.DCI was defined as cerebral infarction and/or neurological impairment after a SAH.The qualitative and quantitative CTP parameters and clinical data were compared between patients with and without DCI.The diagnostic performance of clinical data,mean and lowest CTP parameters were evaluated by receiver operating characteristic(ROC)analyses.A logistic regression analysis was performed to determine the DCI predictors.Results: The study evaluated 191 of the 252 consecutive patients.There were 57 patients(57/191;29.8%)who developed DCI during hospitalization.There were 96 cases of aneurysms in anterior circulation,75 cases in posterior circulation,13 cases in subtentorial cerebellum and 7 cases in multiple aneurysms.There were 13 cases of CVS in DCI group(n = 8)and 5 cases in non-DCI group(n = 5).The incidence of CVS in two groups was statistically significant(P=0.010).The incidence rate of DCI was significant difference in the three qualitative CTP patterns(P<0.001).Patients with diffused hypoperfusion had the highest incidence rate of DCI(43%,46/107).We observed differences in the following parameters of DCI patients compared to non-DCI patients during whole brain CTP: lower CBF and CBV,and longer MTT,TTD,TTS,and TMax.In the CTP quantitative analysis,there were significant differences in the mean CTP parameters between the two groups(P<0.05).There were significant differences in the minimum value of CBF and the maximum value of the MTT,TTD,TTS and TMax between the two groups(P<0.05),but there was no significant difference between the two groups in the minimum CBV value(P>0.05).The patients with higher Hunt-Hess grade(P<0.001)and lower GCS score(P<0.001)were more likely to develop DCI.Patients with cerebral edema(P=0.045)and hydrocephalus(P<0.001)were more likely to develop DCI(P<0.001).The areas under the curve(AUC)of mean CTP parameters were larger than the lowest CTP parameters.We found that the mean TMax had the largest AUC of 0.726(95%CI:0.638-0.814),and a cutoff value of 2.240 seconds provided sensitivity of 73.7% and specificity of 71.6% for the early prediction of developing DCI.The Glasgow Coma Scale(GCS)score(OR=0.716,95%CI: 0.565-0.908,P=0.006),cerebral vasospasm(OR=6.117,95%CI: 1.427-26.223,P=0.015),hydrocephalus(OR=3.795,95%CI: 1.327-10.858,P=0.013)and qualitative CTP analysis(OR=3.383,95%CI: 1.686-6.789,P=0.001)were all significant independent predictors of DCI.Conclusion:1.Whole-brain CTP within 24 hours on admission can detect the abnormal changes of cerebral hemodynamics in patients with a SAH at the same time as determining the causes of SAH.2.Whole-brain CTP can predict the occurrence of DCI after a SAH qualitatively and quantitatively,and can provide accurate information for clinical intervention and treatment.3.The mean Tmax value is the best CTP quantitative parameter to predict DCI,its cutoff value is 2.240 seconds.