Application Of CT Perfusion ASPECTS In Endovascular Therapy Of Acute Ischemic Stroke

Background and ObjectiveEndovascular therapy(ET)is currently the most effective treatment for acute ischemic stroke(AIS)with large vessel occlusion(LVO).It is one of the keys for ET to get a good outcome by choosing the right patient through image.Especially the application of CT perfusion image can select the right patient for ET in a more detailed way.In recent years,many large clinical studies have used computer software to analyze CTP images automatically and quantitatively,and the safety and validity have been proved.However,these automation software are expensive and complex to maintain,which is still unavailable in most parts of China.Alberta Stroke Program Early CT Score(ASPECTS)is a simple and easy-to-read scoring system.In practice,there are few studies on the comprehensive evaluation method of CTP ASPECTS,and the optimal threshold is not clear.At the same time,the mismatch between NCCT image and CTP image ASPECTS often occurs in preoperative selection,which makes it difficult for interventional physicians to make treatment decisions.There is no report on how to evaluate such patients and the safety and effectiveness of ET.Through a retrospective analysis of patients with AIS-LVO receiving ET in our center,we intend to have a better understanding of the application of ASPE CTS in preoperative screening of CTP images,and to find a simple and feasible mismatch assessment method.Methods1.Retrospective study of ET patients with circulating LVO from November 2015 to January 2018,who had been hospitalized for 6 to 24 hours before the onset of LVO,ASPECTS(> 5 points)of CTP image cerebral blood volume(CBV),ASPECTS(> 1 points)of CBV and mean transit time(MTT)did not match ASPECTS,and NIHSS(> 10 points)of hospitalization.According to the grouping comparison of good outcome(mRS < 2)and poor outcome(mRS > 2),good outcome indicators were analyzed,and the optimal threshold of CTP ASPECTS image comprehensive evaluation was found by ROC curve analysis.2.A total of 290 ET patients with anterior circulation LVO who were treated continuously from January 2015 to August 2018 were reviewed.CBV ASPECTS(> 6 points)and NIHSS(> 6 points)of CTP images were obtained.NCCT and CBV images were recorded with ASPECTS and the difference between them.According to NCCT-CTP ASPECTS(N-C)<0 and N-C>0 grouping records,the security and effectiveness of the two methods were compared.The safety indicators of the two studies were severe intracranial hemorrhage,symptomatic intracranial hemorrhage and 90-day death.The validity indexes were 7 days in hospital,NIHSS score at discharge and 90 days mRS.ResultsThere were 29 patients in group mRS > 2 and 40 patients in group mRS < 2.The incidence of sICH was 5.8% in all patients,and 5 patients(7.2%)died.Forty patients(58.0%)had good outcomes(mRS < 2),and 12 patients(17.4%)had partial improvement(mRS 3).There was no significant difference in NIHSS score at admission and 7 days NIHSS score between the two groups,but there was significant difference in NIHSS score at discharge.The NIHSS score of mRS < 2 group was nearly 14 points lower than another group(average,18.03 vs.4.5,P = 0.000).CBV ASPECTS was higher(median,9 vs.7,P = 0.002),MTT ASPECTS score was lower(median,4 vs.5,P = 0.013),and there were wider mismatched areas(median,4 vs.2,P = 0.000),and MTT/CBV ratio was higher(median,4 vs.2,P = 0.000).The time points of mRS < 2 groups were shorter,PTR had significant difference(median,57.0 vs.81.0,P = 0.004).CBV-MTT,MTT/CBV and CBV were selected to evaluate the diagnostic efficacy.ROC showed that AUC was 0.893(CI 0.815-0.971),which was higher than all the individual predictive indicators.The three thresholds were 2,2 and 7 respectively.There were 25 patients with N-C < 0 and 119 patients with N-C ? 0.The good outcome rate in the study was 60.4%(87/144),severe intracranial hemorrhage was 12.5%(18/144),symptomatic intracranial hemorrhage(sICH)was 3.5%(5/144),and mortality was 5.6%(8/144).There was no significant difference in severe intracranial hemorrhage,sICH and mortality between the two groups.There was no significant difference in NIHSS score between the two groups at 7 days of hospitalization and at discharge.The 90-day good outcome was also no significant difference in regression analysis(P=0.935),and 20%(5/25)of the patients got mRS 3 score.Multivariate regression analysis showed that bridging therapy(OR=3.030,95% CI=1.202-7.642,P=0.019)and CBV ASPECTS(OR=1.460,95% CI=1.095-1.945,P=0.010)were independent predictors of good prognosis,while NCCT ASPECTS did not have such effect.NIHSS(OR=0.879,95% CI=0.813-0.951,P=0.001)and PTR(OR=0.991,95% CI=0.984-0.999,P=0.032)were negatively correlated with good prognosis.ConclusionIt is a simple,safe and effective method to select patients with late time window LVO using the comprehensive evaluation method of CTP ASPECTS.However,patients with moderate to large low density areas in NCCT and small areas of CBV decline can benefit from ET without increasing the risk of bleeding and mortality.