The Optimal Hypoperfusion Index Ratio To Predict Collateral Circulation And Its Correlation With Secondary Hemorrhagic Transformation

Objective:To investigate the optimal Hypoperfusion Index Ratio(HIR)for predicting collateral circulation of Acute Ischemic Stroke(AIS)and its correlation with secondary Hemorrhagic transformation(HT).Methods:A total of 62 patients with anterior circulation AIS who received one-stop head CT examination within 24 hours of onset from January 2020 to February 2023 and received no treatment before hospital without bleeding were retrospectively collected.The original image of head one-stop CTA examination was imported into Philips Intelli Space Portal post-processing workstation for reconstruction to acquire dynamic /4D-CTA vascular images.Two independent investigators assessed the pre-treatment dynamic/4D-CTA collateral circulation of the enrolled patients based on the modified American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology(ASTIN/SIR)collateral circulation score,with a score of 0-2 being defined as poor collateral circulation and a score of 3-4 being defined as good collateral circulation,and divided the 62 patients into a poor collateral circulation group and a good collateral circulation group.The Kappa consistency test was used to evaluate the agreement between the two investigators on the dynamic/4D-CTA collateral circulation scores.The original image of head one-stop CTP examination was imported into the Shukun brain Perfusion intelligent analysis software(version 2.1.2)to automatically analyze the volumes of time to maximum(Tmax)of the residual function greater than 4s,6s,8s,10 s in the affected brain tissue of the enrolled patients,defined and manually calculate HIR(1)=Tmax>10s volume/Tmax>4s volume,HIR(2)=Tmax>10s volume/Tmax>6s volume,HIR(3)=Tmax>8s volume /Tmax>4s volume and HIR(4)=Tmax>8s volume /Tmax>6s volume.The Spearman correlation analysis was used to investigate the correlation between the four HIRs and collateral circulation,the receiver operating characteristic curve(ROC)was used to explore the value of the four HIRs on predicting poor collateral circulation to obtain the optimal HIR.The 62 enrolled patients were divided into Hemorrhagic transformation(HT)group and non-Hemorrhagic transformation(n HT)group according to head CT review within 7days after admission.Spearman correlation analysis was used to study the correlation between the optimal HIR and hemorrhagic transformation,and ROC curve was used to explore the predictive efficacy of the optimal HIR for hemorrhagic transformation.The Hemorrhagic transformation(HT)group was further divided into Parenchymal Hemorrhage(PH)group and Hemorrhagic Infarction(HI)group according to the European Cooperative Acute Stroke Study(ECASS)hemorrhagic transformation classification.Binary logistic analysis was used to study the independent predictors of Parenchymal Hemorrhage.The baseline clinical data such as gender,age,hypertension,admission emergency laboratory tests,platelet/lymphocyte ratio(PLR),neutrophil/lymph ocyte ratio(NLR),time to onset of one-stop CT and admission NIHSS score were collected from 62 patients.Two independent samples t test,Mann-Whitney U test,Chisquare test and Fisher exact probability method were used for comparison between groups.P < 0.05 was considered statistically significant.Results:1.Among the 62 patients,there were 37 cases in the poor collateral circulation group and 25 cases in the good collateral circulation group.There were no significant differences between the two groups in baseline clinical data such as gender,age,hypertension,emergency laboratory indicators,PLR,NLR,and time to one-stop CT examination(P>0.05);The NIHSS score,HIR(1),HIR(2),HIR(3),HIR(4)were statistically significant between the two groups(P<0.001).The four HIRs were all negatively correlated with the collateral circulation with HIR(3)having the strongest negative correlation(r=-0.543,P<0.001),and the area under the ROC curve for predicting the poor collateral circulation was the largest,which was 0.839,the cut-off value was 0.316,the sensitivity was 78.4%,and the specificity was 84.0%.2.Among the 62 patients,there were 34 cases in the hemorrhagic transformation group and 28 cases in the non-hemorrhagic transformation group.There were no significant differences between the two groups in gender,age,hypertension and other baseline clinical data,emergency laboratory test indicators,PLR,NLR,and time to onestop CT examination(P>0.05).There were significant differences between the two groups in NIHSS score and the optimal HIR confirmed to be the HIR(3)(P<0.05).The optimal HIR was positively correlated with the hemorrhagic transformation(r=0.335,P<0.05),the area under ROC curve for predicting hemorrhagic transformation was0.694,the cut-off value was 0.316,the sensitivity was 70.6%,and the specificity was67.9%.3.Among the 34 patients with hemorrhagic transformation,there were 20 cases in PH group and 14 cases in HI group.The difference of the optimal HIR between the two groups was statistically significant(P<0.05).Binary logistic analysis showed that the optimal HIR was an independent predictor of parenchymal hemorrhage(OR=164.761,P<0.05,95%CI:2.500～10860.435).Conclusion:The Hypoperfusion Index Ratio defined as Tmax>8s volume /Tmax>4s volume can be the optimal HIR for predicting collateral circulation in patients with anterior circulation AIS which is negatively correlated with collateral circulation,and the larger the HIR,the worse the collateral circulation.The optimal HIR is positively correlated with the secondary hemorrhagic transformation in patients with anterior circulation AIS,and can independently predict parenchymal hemorrhage.