A Study Of The Correlation Between The Stenosis And Recanaliazation Of Internal Carotid Artery And FLAIR Hyperintense Vessel Sign By CT Angiography And MR Angiography

Objective:1. To evaluate the correlation between intracranial hyperintense vessel sign(HVS) on fluid-attenuated inversion recovery(FLAIR) and the degree of the stenosis of internal carotid artery(ICA). To disclose the mechanism of HVS and its clinical significances.2. To evaluate the change pre-and post carotid endarterectomy(CEA), and assess the worthy of HVS for curative effect evaluation of CEA.Methods:A total of1221patients with both MR FLAIR sequence and carotid angiography were retrospectively analyzed. Eighty-three patients of our cohort were treated with CEA. Patients were divided into ICA stenosis group and none stenosis group. Then, the ICA stenosis group was subdivided into ICA unilateral stenosis group and bilateral stenosis group. Finally, we measured and graded the ICA in the unilateral stenosis group into seven stenotic degrees, they were<50%,50%～59%,60%～69%、70%～79%,80%～89%、90%～99%、100%, respectively. Chi square test was used to analyze the correlation between HVS and ICA stenosis. Spearman-rank correlation was performed to evaluate the correlation between the presence of HVS and stenotic degrees of the ICA. In the group of83patients underwent CEA, imaging data pre-and post operation were compared, focusing on the recovery of the HVS on MR FLAIR imaging.Results:1. HVS on the FLAIR images were observed in125of304patients(41.12%)with ICA stenosis, and in108of917patients (11.78%) without ICA stenosis. The occurrence rate of HVS was significantly higher in patients with ICA stenosis than those without ICA stenosis (χ2=127.289, P<0.001)2. The occurrence rates of HVS were39.3%(90/229) in ICA unilateral stenosis group, and were48%(36/75) in bilateral stenosis group. There was no statistical significance in the occurrence rates of HVS between ICA unilateral stenosis group and bilateral stenosis group.(χ2=1.762, P>0.05).3. The occurrence rates of HVS were15.38%,12.9%,38.46%,33.33%,41.67%,67.86%,85.71%in the seven stenotic degrees, respectively. There was a significant positive correlation between the occurrence rates of HVS and the stenotic degrees of ICA (r=0.929, P<0.001).4. The presence of HVS was strongly assosciated with the circle of Willis,the presence of HVS (93.33%) was significantly higher in the group of non collateral flow from the circle of Willis than that (56.25%) in the group of collateral flow from the circle of Willis.(χ2=12.927, P<0.001)5. HVS was disappeared in31patients after CEA in40patients with HVS on preoperational MR images. The remaining HVS in9patients was attributed to the failure of completely recanalization of ICA.Conclusion:1. A close relationship was exist between HVS and ICA stenosis. The presence of HVS indicated a high probability of the existence of ICA severe stenosis. A further assessment on ICA was necessary.2. HVS was disappeared after successful CEA, indicated that HVS can be a useful marker for the evaluation of consequence with CEA.