Changes In Cerebral Hemodynamics After Cranial And Cervical Arterial Stenting: Evaluation With CT Perfusion Studies

Purpose To explore the application of CT perfusion in cranial and cervical arterial stenting.Methods CT perfusion(CTP) were performed in 20 patients before and after stenting. CTP maps of every patient were compared before and after stenting. Relative cerebral blood flow(rCBF), relative cerebral blood volume(rCBV) and relative time to peak(rTTP) of direct and indirect vascular territories of stenting artery, which were respectively calculated by comparing with values of a chosen region, compared with cerebral blood flow(CBF), cerebral blood volume(CBV) and tine to peak(TTP) before stenting. Correlation were analyzed between changes of perfusion parameters and stenotic ratio, improving degree of corresponding vessels. Perfusion parameter changes of corresponding vascular regions with preoperative perfusion defect was compared with intact group. Bland-Altman method was used to find the limits of agreement of pre-and postoperative TTP and CBF values of indirect vascular territories. Direct vascular territories with significant changes were found with these limits and compared with findings in maps.Results Five patients' perfusion maps were found with visible changes. There was a significant difference(P<0.05) between pre-and postoperative for TTP and CBF in direct territories group. Postoperative rTTP values(95.99±20.60) is lower, rCBF values(18.32±4.97) is slight higher. There was no significant difference for rCBV in two groups. No significant differences were founded between pre-and postoperative in indirect territories group. Moderate positive correlation(r=0.323,P<0.05) was found between changes of CBF values and stenotic ratios, and moderate negative correlation(r=-0.493,P<0.001) between TTP and it. Perfusion parameter changes of corresponding vascular regions with preoperative perfusion defect was higher than intact group(P<0.05). Limits of agreement of pre-and postoperative of indirect vascular territories was(-6.60 s×10-1,5.35 s×10-1)( difference method) for TTP values and(0.83, 1.33)(ratio method) for CBF values. Fifteen direct vascular territories with significant changes, which were all improved in TTP maps, were founded with TTP limits of agreement. Significant changes were founded with CBF limits of agreement only in one direct vascular territory.Conclusions CT perfusion is a useful tool to evaluate the therapeutic effect after cranial and cervical arterial stenting. The application of CT perfusion in evaluating stenting effect was widened by dynamically choosing regions according to stenting position. Analyzing preoperative perfusion maps is helpful to select operative patients. Hemodynamic changes of stenting were more easily to be detected by combining quantitative analysis with Bland-Altman limits of agreement and qualitative analysis.