Diagnosis Of Acute Ischemic Stroke By 3D-pCASL Combined With DWI And Head-neck MRA

Objective:To observe and analyze the imaging findings of three dimensional pseudo-continuous arterial spin labeling?3D-pCASL?,diffusion weighted imaging?DWI?,and head-neck magnetic resonance angiography?MRA? in acute ischemic stroke?AIS?,so as to explore the diagnostic value of the combined application of the three in AIS.Methods:120 suspected AIS patients were collected from Huaihua First People's Hospital from January 2017 to December 2018,and 80 of them were finally confirmed with the diagnosis.Patients were scanned with Philips Ingenia 3.0T magnetic resonance head and neck coils;meanwhile,3D-pCASL,DWI and head-neck MRA data were obtained,and the imaging findings of these three in AIS were observed.In addition,the differences in apparent diffusion coefficient?ADC? value and regional cerebral blood flow?rCBF? value between the affected side and the contralateral boot image area were measured,respectively,for Wilcoxon signed rank sum test.Afterwards,the receiver operating characteristic?ROC? curves of the three methods in separate diagnosis and combined diagnosis of AIS were plotted;in addition,the area under the curve?AUC?,sensitivity,specificity and Yoden index were calculated.Then,head-neck vascular stenosis was classified as normal,mild stenosis,moderate stenosis,severe stenosis and occlusion to carry out Spearman correlation analysis with the abnormal 3D-pCASL and DWI areas,so as to analyze the correlations among these three.Results:Among the 80 AIS patients,72 showed reduced rCBF on 3D-pCASL perfusion image,while 8 showed no obvious abnormality in 3D-pCASL perfusion.Arterial transit artifact?ATA? was observed in 28 of 72 patients with hypoperfusion.74 out of the 80 AIS patients displayed increased signal on DWI image,with limited diffusion on ADC image,while no obvious abnormal hyperintensity was observed on the DWI images of the remaining 6 cases.Among the 80 AIS patients,20 had normal blood vessels,21 had mild stenosis,19 had moderate stenosis,12 had severe stenosis,and 8 had occlusion.The ADC values in affected side and contralateral boot image area were?402.17±102.05?×10^-6mm²/s and ?691.56±63.72?×10^-6mm²/s,respectively(P<0.01^**),and the difference between the two was statistically significant.In addition the rCBF values in affected side and contralateral boot image area were 15.42±3.15?ml/100g/min? and 50.45±8.94?ml/100g/min?,respectively(P<0.01^**),and the difference between the two was statistically significant.The AUC of 3D-pCASL in diagnosing AIS was 0.895(95% confidence interval CI,0.838-0.953,P<0.001^***),the sensitivity was 0.821,the specificity was 0.976,and the Youden index was 0.797.By contrast,the AUC,sensitivity,specificity and Youden index of ADC value in diagnosing AIS were 0.962(95%CI,0.927?0.998,P<0.001^***),0.936,0.976 and 0.912,respectively;while those of MRA in diagnosing AIS were 0.616?95% CI,0.520-0.721,P<0.05^*?,0.69,0.619 and 0.209,respectively;and those of the combined application of 3D-pCASL,DWI and MRA in diagnosing AIS were 0.989(95% CI,0.973-1.000,P<0.001^***)0.987,0.976 and 0.963.ASL showed significantly positive correlation with DWI(r=0.895,P<0.01^**),3D-pCASL showed moderately positive correlation with MRA(r=0.558,P<0.01^**),and DWI displayed moderately positive correlation with MRA(r=0.535,P<0.01^**).Conclusion:3D-pCASL is a non-invasive technique to objectively reflect the blood perfusion in acute cerebral infarction area,which can diagnosis AIS in an non-invasive and accurate way.3D-pCASL is significantly positively correlated with DWI,while 3D-pCASL and DWI are moderately positively correlated with MRA,suggesting that cerebral blood flow and diffusion can better reflect the pathological change of AIS.The combined application of 3D-pCASL,DWL and head-neck MRA in diagnosing AIS can attain the greatest AUC,as well as highest sensitivity and specificity,which can more comprehensively and accurately diagnose AIS,thus providing earlier and more accurate diagnosis and treatment foundation for clinic.