Multimodality Mri Evaluation Of Carotid Atherosclerotic Disease On Brain Tissue

Purpose:Multimodality MRI was used to investigate changes in cerebral perfusion as the severity of carotid atherosclerosis gradually increasing.At the same time,we analyzed the components of carotid plaque to evaluate the stability of the plaque,and observed the status of lacunar infarction in the blood supply area of the responsible blood vessel.Finally,we aimed to achieve information about the effects of the components of the carotid plaque of the responsible blood vessel on the intracranial tissue.Methods: 39 patients with unilateral carotid artery stenosis were included in the experimental analysis.According to the degree of stenosis,patients were divided into four groups.High-resolution magnetic resonance imaging(HRMRI)was used to determine the degree of stenosis and the plaque composition.The stability of the plaque was analyzed using VPD software,while dynamic susceptibility contrast perfusion imaging(DSC-PWI)and arterial spin labeling(ASL)were performed to evaluate the hemodynamic changes in brain tissue.The perfusion parameters were measured in all patients,including the temporal parietal and frontal lobe and calculated the relative values.By self-control,it is analyzed whether there is statistical significance in each group of differences.Evaluated the correlation between stenosis and perfusion values using rank correlation coefficient(Spearman).At the same time,the relative perfusion values of the temporal parietal lobe and the frontal lobe of each group were compared and analyzed.Intra-class Correlation Coefficient(ICC)was used to analyze the relationship between PWI and ASL in the semi-quantitative measurement of CBF.At the same time,the patients were divided into vulnerable group(26 cases)and stable group(13 cases)according to the stability of plaque.Observing the occurrence of lacunar infarction in the blood supply area of the responsible blood vessels through MRI scan.The chi-square test was used to analyze the correlation between plaque vulnerability and lacunar infarct caused by small emboli shedding.Result:1.Changes of perfusion in the ipsilateral frontal lobe and temporal parietal lobe,When the unilateral carotid artery is stenosisIn 39 cases,nine cases showed abnormal frontal perfusion,and 19 cases abnormal perfusion of the temporal parietal lobe,while they were mostly present in the severe and occlusion group.Cerebral hemodynamic abnormalities and changes in perfusion parameters were more likely to occur in the temporal parietal lobe than in the frontal lobe.(P<0.05).Taking the temporal parietal lobe as an example,the degree of carotid artery stenosis is positively correlated with rMTT,rTTP,and rCBV(P<0.01).2.The effect of the stability of carotid artery plaque on the brain tissueOf the 39 patients,the vulnerable group included 26 cases,of which 16 cases(61.5%)had lacunar infarction or TIA,and the stable group included 13 cases,of which 3 cases(23.1%)had lacunar infarction or TIA.Statistical analysis showed that the probability of occurrence of lacunar infarction or TIA in the vulnerable group was greater than that in the stable group.3.Analysis of the consistency between PWI and ASL in measuring perfusionPWI and ASL have better consistency when measuring CBF semi-quantitatively(P = 0.036).Conclusion: Severe or occluded carotid artery may result in insufficient blood supply to the distal vessels,reduced perfusion of frontal and temporal parietal lobe;while plaque components are complex and unstable,emboli will fall off and block the distal vessels.both will eventually lead to TIA and stroke.