The Application Of CTA In The Imaging Evaluation Of Acute Ischemic Stroke

Purpose:The study aimed to determine the value of head CTA used to evaluate collateral flow and infarct core in patients with large-vessel occlusion-related acute ischemic strokes(LVO-AIS).Methods:Clinical and imaging data of patients with AIS caused by LVO from January 2016 to May 2018 were collected.Capillary index score(CIS)was calculated from CTA and DSA images respectively to evaluate cerebral collateral flow,which was applicable to MCA occlusion-related AIS only.Patients were classified into the favorable collateral flow group if CIS was ≥2 points(fCIS),and into the poor collateral flow group if CIS was <2 points(pCIS).Agreement between the methods was evaluated using the Kappa test.Perfused blood volume(PBV)was reconstructed from CTA and NCCT images with three-dimensional Neuro PBV software to predict infarct core,which was applicable to all patients.We estimated infarct size via ASPECTS,which was calculated on PBV and follow-up MR-DWI images within 3 to7 days respectively.ASPECTS on DWI was regarded as the gold standard to evaluate the accuracy of PBV.Results:There were 79 patients with LVO-AIS in total,and 40 patients of them were caused by MCA occlusion and completed DSA.CIS on DSA and CIS on CTA had high consistency(Kappa = 0.72),and the diagnostic accuracy of CTA was 87.5%.The 90-day mRS was higher in the pCIS group(p = 0.04).Favorable CIA on CTA,low blood glucose at admission and good recanalization were significantly correlated with good outcome.The consistency of PBV-based ASPECTS and DWI-based ASPECTS was 0.78,which was 0.73 and 0.80 respectively in the subgroup of mechanical thrombectomy and non-endovascular treatment.ROC curve analysis revealed PBV-ASPECTS(AUC=0.677;95% CI:0.516-0.838;P=0.047)wasn’t a proper indicate to predict favorable functional outcome in patients with LVO-AIS.Conclusion:Head CTA played an important role in the imaging evaluation ofpatients with LVO-AIS,which could not only reflect the collateral cerebral flow,but also estimate infarct core to provide more useful clinical information.