The Value Of Multimode CT In Predicting Collateral Status,Hemorrhage Transformation And Prognosis In Acute Ischemic Stroke

PART 1 Evaluation of Lateral Branch Circulation and Blood Flow Status by Dynamic CTA and CTPObjective: Collateral is related to the clinical prognosis of patients with acute ischemic stroke(AIS).In this study,dynamic CTA derived from whole brain CT perfusion data was combined with CT perfusion(CTP)parameters to explore its application value in collateral and perfusion status,and prognostic predictive ability for intravascular treatment of AIS.Methods : 31 patients with acute ischemic stroke who underwent one-stop CTA+CTP examination before endovascular treatment were included retrospectively,The range,velocity and general condition of collateral were evaluated based on dynamic CTA,and the consistency of the collateral scores was evaluated by comparing them with collateral score based on digital subtracted angiography(DSA-CS).Cerebral blood volume(CBV),low perfusion index ratio(HIR)and core infarct volume and their ratios rCBV were measured.The correlation between dynamic CTA score and rCBV and HIR was analyzed.Three months later,the patients were followed up with the modified Rankin Scale(m RS),defined as m RS ≤2,and divided into good prognosis group.The correlation between dynamic CTA and CTP parameters and prognosis was analyzed.Results: 1The dynamic CTA score was consistent with DSA-CS score system(Kappa=0.876,P < 0.001);2.There was a correlation between rCBV,HIR and dynamic CTA score.HIR and dynamic CTA score,rCBV and HIR had a good correlation(r=-0.530,P=0.002;R =-0.651,P < 0.001);3.According to the results of MRS follow-up for 3 months,17 patients(54.84%)were in the good prognosis group and 14 patients(45.16%)were in the poor prognosis group.There were statistically significant differences in dynamic CTA score,core infarction volume,rCBV and HIR between the good prognosis group and the poor prognosis group(P < 0.05).Conclusions: 1.The evaluation of collateral by dynamic CTA based on CTP reconstruction can predict the prognosis of patients with AIS after endovascular treatment;2.HIR can be used as an effective indicator of anterior collateral circulation in patients with AIS after endovascular treatment;3.Core infarct volume,rCBV and HIR can affect the prognosis of patients with AIS after endovascular treatment.PART 2 The value of multimode CT in predicting hemorrhagic transformation in acute ischemic strokeObjective: Hemorrhagic transformation is one of the natural outcomes in patients with acute ischemic stroke(AIS).In this study,dynamic CTA derived from whole-brain CT perfusion data was combined with CT perfusion imaging(CTP)parameters to explore the multimodal CT value to the diagnosis of acute ischemic stroke hemorrhage transformation.Methods : 50 patients with acute ischemic stroke who underwent one-stop CTA+CTP examination before treatment were included retrospectively,measured cerebral blood flow(CBF),cerebral blood volume(CBV),mean transit time(MTT),time to peak(TTP),transit time to impulse residue function peak(Tmax),permeability surface area product(PS)and their ratios r CBF,rCBV,r MTT,r TTP,r Tmax,r PS were calculated.According to follow-up imagings,patients were divided into HT group and non-HT group,compare the differences of various parameters between the two groups,and the dynamic CT angiography(CTA)scores between them,to explore whether there is a correlation between various parameters and hemorrhagic transformation.Results: In 50 cases,CBF,CBV,r CBF,rCBV in HT group were lower than that in the non-HT group(P<0.05);MTT,PS,r PS in the HT group were significantly higher than that in the non-HT group(P < 0.05);The correlation between r PS and HT was strongly positive(r=0.610,P<0.01);PS,MTTwere moderately positively correlated with HT(r=0.587,0.522,P < 0.01);CBF,CBV(r=-0.617,-0.675,P < 0.01)had a strong negative correlation with HT,r CBF,rCBV(r=-0.549,-0.528,P <0.01)had a moderately negative correlation with HT.CBV showed the best diagnostic efficacy for hemorrhagic transformation,with an AUC of 0.956,a sensitivity of 0.917,and a specificity of 0.868;2.The incidence of hemorrhagic transformation in the group with good collateral circulation(5/41,12.20%)was lower than that in the group with poor collateral circulation(7/9,77.78%),and the difference was statistically significant (P<0.01);3.HT was better evaluated by r PS *HIR with an AUC of 0.954,sensitivity of 1,and specificity of 0.921.Conclusions: 1.The evaluation of collateral circulation by dynamic CTA based on CTP reconstruction can predict HT in AIS patients;2.Among the CTP parameters,CBV had the best diagnostic efficiency for hemorrhagic transformation;3.The new model r PS *HIR has higher HT diagnostic performance.