Multimodal CT Evaluation Of Ischemic Penumbra And Collateral Circulation In Ischemic Stroke

Objectives:To evaluate the value of multimodal CT in the diagnosis,treatment and prognosis of ischemic stroke.1.To discuss the value of multiphase CTA in evaluating collateral circulation based on the results of DSA.2.To explore the correlation between CT perfusion parameters and collateral circulation,and evaluating the value of collateral circulation.3.To explore the relationship between lesion volume after treatment,mRS score and collateral circulation.Methods:1.41 patients were enrolled who were clinically diagnosed as the first onset of ischemic stroke in our hospital from September 2016 to 2018.All patients underwent multi-modal one-stop with single scan(NCCT+CTP15cm)or multi-modal one-stop with two scan times(NCCT+CTP10CM+carotid and head CTA).The second way of scanning was 10 minutes between CTP and CTA.The second generation of flash dual-source CT of Siemens,Germany,adopted low dose cradle technique for plain scan and CTP scan with 80kV,80mAs and intervals of 1.5seconds,a total of 33 dynamics data were collected.Neuro-DSA scanning mode was used for head-neck CTA.Siemens MMWP workstation ran VP Neuro-software,4 perfusion parameters and images,time-density curves(TDC)were obtained.According to the TDC curve,the dynamic CTA images of contrast agent flow from artery to vein were obtained,namely multi-phase CTA images.Patients underwent CT or MR scan for reexamination.It was divided into four group:hyperacute stage,acute stage,subacute stage and chronic stage according to clinical manifestation.The enrolled collateral circulation included primary and secondary vessel,and was divided into poor,general and good.Compared with the DSA results,the value of multi-phase CTA in the display of collateral circulation was analyzed,and the display of collateral circulation in each phase was evaluated.In CTP scanning,CBV remained unchanged or slightly increased,TTP delayed was defined as the existence of collateral circulation,the diagnostic value was evaluated by comparing with the results of DSA.The IP and infarcted core were distinguished br the results of CBF-CBV mismatch and CBF/CBV>1.2.The effect of multiphase CTA on prognosis was evaluated compared with the clinical mRS score of 30-90 days follow up after treatment and infarction volume calculated by CT or MRI = the maximum long diameter*wide diameter*the layer number of infarcts*thickness*?/6.Results:1.General situation:in 41 cases,there were 2 cases of hyperacute ischemic stroke,7 cases of acute stage,13 cases of subacute and 19 cases of chronic stage.2.CT plain scan results of hyperacute infarction were negative;the difference between CT plain scan and CTP in acute phase was statistically significant(P<0.05);there was no difference between CT plain scan and CTP in subacute and chronic stage(P>0.05).3.The diagnosis of IP in different ischemic stages by CTP:there were 2 cases of hyperacute,6/7 cases of acute phase,10/13 cases of subacute stage,13/19 cases of chronic stage.4.Multiphase CTA and DSA were consistent in showing secondary collateral circulation:there were 9/10 cases of poor circulation,18/19 cases of general circulation and 14/12 cases of good circulation.5.Multiphase CTA did not show statistically significant difference in time-analysis of secondary collateral circulation(P>0.05),indicating that multiphase CTA could evaluate secondary collateral circulation than conventional single-phase CTA better.6.There was no significant difference between the CTP parameters and DSA in evaluating the primary collateral circulation.7.The relationship between CTP parameters and DSA in evaluating secondary collateral circulation:the difference of CBV,CBF and MTT were statistically significant(P<0.05).8.The relationship between final infarction volume,mRS score and multiphase CTA evaluation of secondary collateral circulation:according to the collateral circulation,it was divided into three groups:poor,general and good.The difference in the final infarction volume and mRS score between the three groups was statistically significant(P<0.05).Patient with good collateral circulation had better curative effect accounting for 83%(10/12),and patients with poor collateral circulation accounted for 70%(7/10).Conclusions:1.Multimodal CT examination if ischemic stroke could identify early lesions,CTPwas used to determine the existence of IP in low perfusion area,whether there was stenosis and occlusion in intracranial vessels,assess the secondary collateral circulation in diseased area accurately.Especially for acute ischemic stroke,it is a rapid and noninvasive examination method.2.The CT examination of hyperacute and acute ischemic stroke should be performed with CT plain scan and CTP.3.IP existed in ischemic stroke of different clinical stages,and it still existed in patients beyond the treatment window.Multiphase CTA is necessary to evaluate the secondary collateral circulation.4.CTP could accurately,indirectly evaluate the primary and secondary collateral circulation,but it could not determine the position and degree of collateral circulation.5.The evaluation of secondary collateral circulation by multiphase CTA was positively correlated with the prognosis after treatment.