Quantitative Analysis Based On Multimodal CT In Acute Ischemic Stroke With Large Vessel Occlusion Of Anterior Circulation

Part I Multimodal CT Characteristics of large artery atherosclerosis and cardioembolism acute ischemic stroke: a comparative studyObjective:To investigate the difference in infarction characteristics between large artery atherosclerosis and cardioembolism acute ischemic stroke(AIS).To evaluate the difference in characteristics between acute ischemic stroke(AIS)patients with large artery atherosclerosis and cardioembolism,through quantifing the ischemic changes of brain tissue using quantitative analysis based on multimodal CT imaging,and to guide physicians to make precise treatment strategies.Methods:A retrospective study was done on 99 AIS patients,who were admitted to Emergency Room of our hospital and underwent multimodal computed tomography(CT)after admission and before treatment.Forty-six of 99 AIS patients had large artery atherosclerosis and 53 had cardioembolism.The NIHSS score and GCS score on admission,infraction core and ischemic penumbra volumes and the volume difference,and vascular occlusion rates of posterior circulation and large artery were compared between the two groups.Results:Compared with the cardioembolism group,the NIHSS score was significantly lower and the GCS score was significantly higher in the large artery atherosclerosis group(9.5[2.0,16.0] vs 15.0 [6.0,24.0],Z=2.31,P<0.001;13.52±2.69 vs 11.60±3.31,t=1.04,P = 0.002).The volumes of infarction core and ischemic penumbra in the cardioembolism group were 1(0,22)m L and 64(30,126)m L,respectively,and were both significantly larger than those in the large artery atherosclerosis group(0 [0,1] m L and 10[0,70] m L;Z=3.85 and 3.43,both P<0.01).However,the volume difference of ischemic penumbra and infraction core was not significantly different between the cardioembolism and large artery atherosclerosis groups(46 [4,103] m L vs 10 [0,64] m L,Z=1.92,P>0.05).The large artery occlusion rate and posterior circulation occlusion rate were both significantly different between the large artery atherosclerosis and cardioembolism groups(30.43% [14/46] vs 50.94% [27/53] and 36.96% [17/46] vs 9.43% [5/53];?2=11.82 and6.77,both P<0.001).Conclusion:The clinical symptoms,cerebral changes and intracranial large artery changes are different in AIS patients with large artery atherosclerosis and cardioembolism.Etiology evaluation based on clinical features and multimodal CT examination can help to accurately assess the ischemic state of AIS patients.Part II Multimodal CT predicts outcome value of mechanical thrombectomy for patients with acute ischemic stroke of anterior circulation large vessel occlusionObjective: To retrospectively analyze the clinical data and imaging data of patients with acute ischemic stroke of anterior circulation large vessel occlusion treated by mechanical thrombectomy,and to explore the value of multimodal CT imaging in predicting their outcome.Methods: Patients with suspected acute ischemic stroke were collected from January2017 to June 2019 in our hospital.All patients underwent multimodal CT imaging before surgery.Patients with anterior circulation large vessel occlusion who underwent mechanical thrombectomy were included in the study.The characters and imaging of the patients were analyzed.Patients were divided into poor or good outcome group according to 90-day m RS.A single factor with P <0.2 was selected for multivariate logistic regression analysis,a prediction model was established and cross-validated,and the predictive value of the model was analyzed using the receiver operating characteristic curve.Results: A total of 105 patients were enrolled,including 57 males and 48 females,with a median age of 69(61.5,76.0)years.The median preoperative NIHSS score was(16.40 ±8.04)points.99 patients(94.29%)were successfully recanalized by mechanical thrombectomy,and 31 patients(29.52%)were found to have intracranial hemorrhage.There were 40 patients with poor outcome and 65 patients with good outcome.Multivariate logistic analysis showed that low NIHSS score,anterior circulation large vessel occlusion in M1 or M2 segment,and CBF <30% small volume were influential factors for good outcome in patients with acute ischemic stroke before mechanical thrombectomy.Cross validation shows that the model fitted well.The area under the ROC curve was divided into 0.8484(95% CI: 0.780 ~ 0.9169)with a cutoff value of 119.6.The sensitivity was 79.7%,the specificity was 90.0%,the positive predictive value was 92.9%,and the negative predictive value was 73.5%.Conclusion: The small NIHSS score,large occlusion of the anterior circulation in the M1/M2 segment,and small core infarct size were independent influencing factors for good outcome.The multiple logistic regression model established in this study could accurately predict the outcome of mechanical thrombectomy in patients with acute ischemic stroke with anterior circulation occlusion and provide a reference for clinical selection of patients who were suitable for mechanical thrombectomy.Part III The value of quantitative analysis based on multimodal and multiphase CT in evaluating collateral circulation in patients with acute ischemic stroke of anterior circulation large vessel occlusionObjective: To explore the application value of RAPID-generated multiphase maximum intensity projection(MIP)in evaluating collateral circulation in patients with acute ischemic stroke of anterior circulation large vessel occlusion,and to analyze the relationship between collateral circulation and clinical factors and CTP parameters,and to explore the quantitative indicators of collateral circulation classification.Methods: Patients with acute ischemic stroke treated in our hospital from January 2017 to January 2019 were collected.All patients underwent multimodal CT imaging,including NCCT,CTA,and CTP.The CTP data was imported into the RAPID software to automatically generate the multiphase MIP map,and the patients were divided into a collateral circulation poor group(0 to 3 points)and a good collateral circulation group(4 to5 points)according to a six-point sequential scale.The clinical data and CTP parameters were compared between the two groups.Multivariate logistic regression analysis of influencing factors of collateral circulation.Results: A total of 171 patients were included in this group,including 95 males and 76 females.123 patients with poor collateral circulation(71.93%),48 patients with good collateral circulation(28.07%),gender(female vs male),baseline NIHSS,anterior circulation vascular occlusion position,CBF <30%,CBV <38% There was significant difference between Tmax>8s,Tmax>10s,mismatch ratio(?1.8 vs< 1.8),hypoperfusion index ratio(?0.3 vs <0.3),P value <0.05.There was no significant difference in age,gender,time from onset to hospital,smoking,hypertension,diabetes,atrial fibrillation,hemorrhagic transformation,Tmax> 4s,Tmax> 6s in both groups,P value> 0.05.Women had worse collateral circulation than men,with an OR value of 0.410 [95% CI: 0.176-0.955].The collateral circulation with the location of vascular occlusion in M1 segment of middle cerebral artery was worse than that in the distal internal carotid artery,with an OR value of0.098 [95% CI: 0.036-0.267].The collateral circulation with the location of vascular occlusion in M1 segment of middle cerebral artery was worse than that in the distal internal carotid artery,with an OR value of 0.160 [95% CI: 0.055-0.466].A large CBF <30% volume indicated a poor collateral circulation with an OR value of 0.968 [95% CI: 0.951-0.985].Conclusion: The multiphase MIP automatically generated by RAPID was a convenient method for evaluating collateral circulation in patients with acute ischemic stroke.Women,Vascular occlusion in M1 / M2 segment of middle cerebral artery and volume of CBF <30%increase were related to poor collateral circulation.Part IV Application of ASPECTS score based on multimodal CT in acute ischemic stroke patients with anterior circulation large vessel occlusionObjective: To evaluate the diagnostic performance of Automated(Auto)-ASPECTS,noncontrast CT(NCCT)-ASPECTS and CT perfusion(CTP)-ASPECTS for early ischemic changes(EICs)in acute ischemic stroke(AIS)patients with anterior circulation large vessel occlusion(LVO)and to explore which scoring method is most suitable for predicting the clinical outcome.Methods: Patients with AIS who had proximal LVO of the anterior circulation at the emergency cerebrovascular disease center of our hospital from January 2019 to June 2019 were collected.All patients underwent multimodal CT(including NCCT,CTA and CTP)examinations before treatment.Eighty-one patients with anterior circulation LVO were retrospectively enrolled and grouped as having a good(0~2)or poor(3~6)clinical outcome using a 90-day modified Rankin Scale score.Clinical characteristics and CT parameters were compared between the patients with good and poor outcomes.Differences in scores obtained with the three scoring methods were assessed.Diagnosis performance and receiver operating characteristic(ROC)curves were used to evaluate the value of the three ordinal or dichotomized ASPECTS methods for predicting the clinical outcome.Results: Eighteen patient were excluded,and finally Sixty-three patients were included,with 36(57.1%)patients having good clinical outcome.The NIHSS score,r CBF<30%,r CBV<38%,Tmax>4s,Tmax>6s,Tmax>8s,Tmax>10s,and hypoperfusion index(HPI)were significantly higher in the poor outcome group than in the good outcome group(all P<0.05),and there were no significant differences in age,gender,time from onset to admission,high density of middle cerebral arteries,location of vascular occlusion,treatment methods,and intracerebral hemorrhage(all P<0.05).Significant differences were observed in the ordinal or dichotomized Auto-ASPECTS,NCCT-ASPECTS and CTP-ASPECTS between the patients with good and poor clinical outcome(all P<0.01).The areas under the ROC curve(AUCs)of the ordinal and dichotomized CTP-ASPECTS was higher than that of the other two methods(all P<0.01),but the AUCs of the Auto-ASPECTS was similar to that of the NCCT-ASPECTS(P>0.05).Conclusison: The CTP-ASPECTS is superior to the Auto-and NCCT-ASPECTS in detecting EICs in LVO.CTP-ASPECTS with a cutoff value of 6 is a good predictor of the clinical outcome at 90-day follow-up.