To Explore The Application Value Of DWI/FLAIR Mismatch In Predicting The Onset Time Of Acute Ischemic Stroke

Objective:To explore the application value of fluid-attenuated inversion-recovery sequence(FLAIR)./diffusion-weighted imaging(DWI)mismatch in the prediction of acute ischemic stroke(AIS)onset time,we analhyzed the matching and time distribution of the FLAIR and DWI in acute ischemic stroke patients with definite onset time.We speculated the possibility of initial onset time of AIS patients with unknown onset time.,which can provide guidance for clinical treatment.Methods:AIS patients of onset time within 6 hours were enrolled from September 2016 to May 2018.and all patients did MRI examination,including DWI.FLAIR.T1-weighted.T2-weighted sequences,PWI.MRA.The clinical data and imaging features of patients were collected.The patients were divided into 3 groups according to onset time:0-180min(group A).180-270min(group B)and 270-360min(group C).The clinical information and MRI findings among three groups were compared.Spearman nonparametric correlation and ROC curve were used to analyze the relationship between onset time and DWI/FLAIR mismatch.Results:The patients were divided into 3 groups according to onset time:0-180min(group A;n=60).180-270min(group B;n=47)and 270-360min(group C:n=27).The mismatch rate of three groups was 90.0%.74.5%and 48.1%respectively.After comparing the three groups of FLAIR and DWI match,there were significant differences between group A and group B(X2=4.544.p=0.033),group A and group C(X2 ?18.423.p=0.000)· group B and group C(x =5.213.P=0.022).Spearman correlation analysis showed that DWI/FLAIR mismatch was negatively correlated with onset time(r?-0.343,p=0.000).ROC analysis showed that the area under the curve of onset time was 0.732(95%CL:0.631-0.833),when the onset time is 181.5 min.the sensitivity was 81.3%and the specificity was 57.8%.Conclusion:As the prolongation of the onset time.DWI/FLAIR mismatch rate decreases gradually,the higher DWI/FLAIR mismatch.the shorter onset time of AIS Therefore.the onset time of AIS patients with unknown onset time may be speculated according to the DWI/FLAIR mismatch.which has great guiding significance for clinical treatment.