Hemodynamics And Functional MRI Study In Patients With Carotid Stenosis

PART1Objective:To evaluate the ability of high resolution MRI examination in detection of carotid atherosclerotic plaque.Methods:We used high-resolution magnetic resonance imaging to scan32cases of patients with clinically diagnosed carotid artery stenosis. The scanning sequence includes TOF, T1W, T2PDW and CE-T1W. Then we compared the degree of carotid stenosis measured with that measured by the gold standard DSA, and evaluated the carotid plaque morphology and components on each-layer image, including the following index:the lipid-rich necrotic core (LRNC), calcification, intraplaque hemorrhage (IPH) and plaque surface rupture.Results:The consistency between black-blood sequence MRI and DSA is better in appraising the degree of luminal stenosis, with the Kappa value of0.897(P<0.001).,High resolution MRI has a unique advantage when study the plaque morphology and composition, because it can clearly identify the plaque components. In our study we also found that the proportion of plaque rupture was correlated with the degree of stenosis significantly, but there is no significant correlation between the degree of stenosis and intraplaque hemorrhage or plaque calcification..Conclusion:MRI scanning could accurately and noninvasively assess stenosis degree of carotid artery lumen, and further analyzed the morphology and components of plaque, laying the foundation for the establishment of carotid artery atherosclerotic plaque model.PART2Objective:First establish the carotid bifurcation hemodynamics model. Then verify and analyze the experimental model.Methods:We used the high resolution MRI to build a three-dimensional reconstruction model, and numerical simulation of three-dimensional rigid model was carried out by using Fluent software. Then hemodynamic parameters associated with carotid atherosclerosis were analyzed, including wall shear stress (WSS), TWSS, OSI and turbulence intensity.Results:The individualized bifurcation hemodynamics model has been built based on the high resolution MRI, and can simulate the carotid artery hemodynamics intuitively within each heartbeat cycle. Numerical simulation of three-dimensional model by using the Fluent software was performed to analyze the relevant hemodynamic parameters of carotid bifurcation atherosclerosis.Conclusion:3D vascular anatomy model could be accurately reconstructed based on the high resolution MRI data. The computer numerical simulation is an effective method to study the hemodynamics of carotid bifurcation. The change of carotid atherosclerosis was related with hemodynamic factors.PART3Objective:To study the clinical characteristics of cognitive impairment and magnetic resonance diffusion tensor imaging manifestations in patients with carotid artery stenosis.Methods:The Mini-Mental State Examination and Montreal cognitive assessment scale were used to evaluate the cognitive function in11cases of patients with severe carotid artery stenosis and the control group. Diffusion tensor magnetic resonance scanning was performed for the patients, and evaluate the ipsilateral and contralateral FA value by using ROI method.Results:The MMSE scale scores of patients with carotid artery stenosis were not significantly different compared with the control group, but less MoCA scale score were found in patients with carotid artery stenosis than those in the control group, which is statistically significant. FA values from the region of interest suggested that white matter lesions mainly located in the junction area.Conclusion:Cognitive impairment was present in the patients with carotid artery stenosis compared with the controls, and diffusion tensor imaging can provide the information of white matter injury.