The Predictive Value Of 3D-pCASL Technique In Progressive Ischemic Stroke

Objective:To explore the predictive value of three dimensional pseudo-continuous arterial spin labeling(3D-pCASL)in progressive acute ischemic stroke(AIS)with unilateral MCA stenosis.Materials and Methods:sixty-six patients with unilateral MCA stenosis>50%who implemented MRI,DWI and MRA on admission were included.According to the whole brain DWI characteristic at the time of admission and within 7 days after admission,the patients were divided into progressive group(n=34)and un-progressive group(n=32).3D-pCASL with two post labeling delays(PLD)of 1525ms and 2525ms were perfomed.Mean cerebral blood flow(CBF1,CBF2)and CBF subtraction images between two PLDs(?CBF=CBF2–CBF1,blood flow of collateral circulation)in regions of interest(ROIs)including bilateral frontal,parietal,temporal and occipital cortices,anterior watershed,internal watershed,posterior watershed and basal ganglia were compared between the two groups.The ROI area was about 30–50 mm~2.Non-parametric test was used to compare each regions' ?CBF at involved side and healthy side in the two groups,the difference was statistically significant with P<0.05.Receiver operating characteristic(ROC)curve was used to evaluate the efficacy of each regions'?CBF in diagnosis of imaging progress of acute ischemic stroke with unilateral MCA stenosis.The area under curve(AUC),sensitivity,specificity and optimal threshold were obtained.The incidence of artery transmit artifact(ATA)in the two groups is analyzed by chi-square test.All patients underwent the Essen stroke risk score(ESRS),the total score of 0to 9 points,it can be divided into Low-risk(0–2points),high-risk(3–9points).Compare the ESRS in the two groups(progressive group and non-progressive group),the difference was statistically significant with P<0.05.Compare the efficacy of ?CBF with a combination of the ESRS and?CBF.Measurement data which obey a normal distribution using Independent Sample T-test,Mann-Whitney U test is used if not obey a normal distribution.Count data is analyzed by chi-square test.Two-tailed P value<0.05 were considered statistically significant.Statistical analyses were performed with the SPSS 20.0 statistical package.Result:1.ATA sign:There were 8 cases of ATA sign occured in progressive group while 17 cases in the non-progressive group.The difference between the two groups was statistically significant(c~2=6.136,P=0.013).2.Involved side had significantly higher?CBF in the temporal cortices than healthy side in the two groups with significantly difference(P<0.05,respectively).3.patients in progress group had significantly lower ?CBF value in the posterior watershed of both side compared with un-progress group(P<0.05,respectively).4.Analysis of ROC curve:The area under curve of?CBF value in posterior watershed at involved side was 0.754,the cut-off value was 8.585ml/(min·100g),the sensitivity and specificity were 0.719 and 0.765.The area under curve of a combination of the ESRS and?CBF in posterior watershed at involved side was0.767,95%CI was 0.649-0.885.5.ESRS:mean ESRS(2.44±0.86)in progressive group while(1.84±1.221)in non-progressive group,the difference was statistically significant(P<0.05).There were 17 cases of high risk and 17 cases of low risk in the progressive group,7 cases of high risk and 25 cases of low risk in the non-progression group.The difference between the two groups'ESRS was statistically significant(c~2=66,P<0.001).Conclusion:1.The sign of arterial transit artifact(ATA)can serve as an indicator for the prognosis of patients with acute ischemic stroke.2.The ?CBF in posterior watershed at involved side is of certain diagnostic value for early stroke progression in patients with acute ischemic stroke caused by unilateral MCA stenosis.3.A combination of the ?CBF value in posterior watershed at involved side and ESRS has a good diagnostic efficiency in progressive AIS.