Correlation With Cerebral Collaterals And Cerebral Hemodynamics In Internal Carotid Atrery Occlusion Evaluated By PWI

Background:The aim of the present study was to assess correlation with cerebral collaterals and cerebral hemodynamics in the patients with unilateral internal carotid artery severe stenosis or occlusion before ophthalmic artery through perfusion-weighted MR imaging.Methods:66patients, diagnosed as unilateral internal carotid artery severe stenosis or occlusion before ophthalmic artery in Neurology department of the first hospital of JiLin university (the degree of stenosis≥70%), were enrolled in the study. Based on TCD findings, patients were classified into7groups:only AcoA group(n=6), only PcoA group(n=8), only OA group(n=9), AcoA and PcoA group(n=9), AcoA and OA group(n=9), PcoA and OA group(n=12), AcoA and PcoA and OA group(n=13).23patients were in ophthalmic artery non-opening group, including AcoA and PcoA group, PcoA group and AcoA group;43patients in ophthalmic artery opening group, including AcoA and PcoA and OA group, PcoA and OA group, AcoA and OA group and OA group. Based on the number of collateral artery, patients were classified into3groups:1collateral pathway group (n=23; AcoA group, PcoA group and OA group),2collateral pathway groups(n=30; AcoA and PcoA group, AcoA and OA group, PcoA and OA group), and3collateral pathways group(n=13; AcoA and PcoA and OA group). Collateral flow hemodynamics were investigated with perfusion-MR imaging by measuring the cerebral blood flow(CBF), cerebral blood volume(CBV), time to peak(TTP) and mean transit time(MTT) in the hemispheres ipsilateral and contralateral to disordered ICA. We chose three regions of interest (ROI) in the level of largest range of putamen, including frontal lobe area, cortical region of MCA distribution area and putamen area. Based on the measurements, the ipsilateral to contralateral ratio and average for each parameter was calculated and respectively recorded rCBF, rCBV, rMTT, rTTP and Average.Results:①We first pooled all the patients together irrespective of their collateral patterns and compared the rCBF, rCBV, rMTT and rTTP with1. rCBV was significantly increased(1.094±0.089, p<0.001), rTTP and rMTT were significantly prolonged(1.057±0.025, p<0.001;1.091±0.078, p<0.001), and rCBF was not significantly different with1(1.001±0.010, p=0.924).②Compared each parameter of PWI between ophthalmic artery opening group and ophthalmic artery non-opening group, rTTP and rMTT were significantly prolonged in ophthalmic artery opening group(1.063±0.025,1.044±0.022, P=0.003;1.110±0.079,1.056±0.063, P=0.005), rCBF or rCBV was not significantly different(1.003±0.104,0.998±0.093, P=0.846;1.102±0.090,1.080±0.088, P=0.334). One-way ANOVA was performed among the groups of ophthalmic artery opening group and the groups of ophthalmic artery non-opening group, no differences were detected for rCBF, rCBV, rMTT and rTTP.③Among the groups of different number of collateral pathways, there were no differences in rCBF, rCBV, rMTT and rTTP.④Compared PWI parameters of the same ROI in7groups with different collateral pathway, all p-values of rTTP, rMTT, rCBV and rCBF were all larger than0.05, suggesting no statically significant. Regardless of difference styles of collateral pathway, three ROI of all patients were compared in PWI parameters. P-value in comparing rTTP was less than0.001, moreover, p-values in any two groups were less than0.05. TTP parameter in the cortical region of MCA distribution prolonged most significantly, followed by putamen area, and finally the frontal region. However, there were no statically significant in rMTT, rCBV and rCBF, whose p-value were all larger than0.05.Conclusion:①、Ophthalmic artery opening in unilateral internal carotid artery occlusive disease may be suggested insufficiency of Willis complement and severe hemodynamic impairment, presumably increasing the risk of ischemic events.②、Patients with unilateral internal carotid artery occlusive disease were in an autoregulatory vasodilatation status with impaired cerebral hemodynamics.③、PWI was available to assess the efficiency of cerebral perfusion provided by cerebral collaterals in patients with unilateral internal carotid occlusive diseases.④、TTP was the most sensitive parameter in PWI to evaluate impaired cerebral hemodynamics.