Study Of Carotid Atherosclerotic Plaque By 3.0T High Resolution Magnetic Resonance Imaging

Objective:The purpose of this study is to evaluate the effect of 3.0 T High Resolution Magnetic Resonance Imaging was used to evaluate the characteristics of carotid atherosclerotic plaque.The differences of general clinical data and plaque distribution characteristics between stable group and unstable group were compared and analyzed.The degree of vascular stenosis associated with plaque in different distribution positions was analyzed.The stability,fiber cap surface condition and internal composition of plaque in symptomatic side group and asymptomatic side group were judged Objective to analyze the difference between the maximum wall thickness and the maximum plaque length in the presence or absence of clinical symptoms,and explore the value of3.0T high-resolution magnetic resonance imaging in determining the nature of carotid atherosclerotic plaque,so as to provide help for clinical diagnosis,early intervention and curative effect analysis.Materials and Methods:A total of 54 patients with carotid atherosclerosis who were treated in our hospital from December 2019 to January 2021 were selected,and all patients were treated with 3.0T HRMRI examination and analysis,collect the general clinical data of patients(including gender,age,hypertension,diabetes,smoking,drinking history,coronary heart disease and blood lipid level),fully analyze the Plaque MRI images,classify the plaque according to the standards set by American Heart Association,collect the relevant characteristics data of carotid plaque(plaque classification,distribution location and plaque corresponding to stenosis of the vascular cavity)According to the degree,the maximum thickness of the wall and the length of plaque,the patients were divided into symptomatic side carotid artery and asymptomatic side carotid artery according to whether there is acute ischemic stroke in cerebral hemisphere in the blood supply area of carotid artery.Finally,the data were analyzed:(1)the difference of clinical data between the stable and unstable groups;(2)the relationship between plaque stability and distribution position;(3)the difference of plaque stenosis in different segments of blood vessels;(4)to judge whether the plaque is stable or not,and the relationship between plaque composition(such as bleeding,lipid core and fibrous cap state)and clinical symptoms Finally,the difference between the thickness and length of plaque in clinical symptoms was analyzed.Analyze the data and draw the conclusion.Results:(1)Analysis and comparison of general clinical data between stable group and unstable group: the proportion of smoking in unstable group was higher than that in stable group(P < 0.05),the proportion of patients with coronary heart disease in stable group was higher than that in unstable group(P < 0.05),and there was no significant difference in gender,age,hypertension,diabetes,alcohol drinking history and blood lipid level between the two groups(P > 0.05);(2)Plaque MRI image analysis: 115 carotid atherosclerotic plaques showed different degrees of annular or eccentric wall thickening on MRI,crescent or meniscus protruding into the lumen.The lipid components of plaques were isointense or slightly hypointense on T2 WI,T1WI,snap and 3D-TOF sequences.When the lipid core necrosis of plaques occurred,there were high and low mixed signals on T1 WI and T2 WI sequences,and low or slightly hypointense on snap and 3D-TOF sequences.When the plaques were bleeding,there were high signals on snap,3D-TOF and T1 WI sequences,and the signals of bleeding focus were different on T2 WI according to the difference of bleeding time;After calcification,there is a low signal state of dot and flake;while the intact fibrous cap shows a low signal band on 3D-TOF,and an equal signal or high signal on Tiwi or T2 WI.After the rupture of fibrous cap,the 3D-TOF image can show the damage,showing a localized high signal shadow protruding into the plaque.The cerebral hemisphere of the symptomatic side of the patient showed abnormal signal due to acute ischemic infarction.T1 WI sequence showed slightly low signal,FLAIR and DWI sequence showed high signal,ADCmap showed low signal.;(3)Plaque classification statistics and distribution comparison: there were 44 cases of type III plaque,14 cases of type IV-V plaque,47 cases of type VI plaque and 10 cases of type VII plaque.There were 54 stable plaques and 61 unstable plaques in the stable group;there were 48 common carotid artery(CCA),35 bifurcations of carotid artery(BIF)and 32 internal carotid artery(ICA)plaques in the stable group;there were statistically significant differences in the distribution of plaques between the two groups(P = 0.004);(4)There was a significant difference in the stenosis rate of carotid artery between different segments(P = 0.035).The distribution of CCA and BIF plaque corresponding to vascular lumen was mainly mild and moderate stenosis,while the distribution of ICA plaque corresponding to vascular lumen was mainly moderate and severe stenosis;(5)The number of plaques on the symptomatic side was 43(37 unstable plaques,6 stable plaques),and the number of plaques on the asymptomatic side was 72(24 unstable plaques,48 stable plaques),the difference was statistically significant(P = 0.001);the fiber cap breakage,bleeding and necrotic lipid core of plaques were also statistically significant between the symptomatic and asymptomatic sides,the P values were 0.001、0.001、0.007;(6)The results showed that the WTmax of symptomatic side(4.56 ±1.40mm)was higher than that of asymptomatic side(3.81 ± 1.58mm)(P = 0.012),but PLmax had no significant difference between the two groups(P = 0.099).Further ROC curve was used to analyze the relationship between WTmax and symptom,and the area under the plaque thickness curve was 0.639,95% CI = 0.537-0.741,WTmax threshold for predicting symptoms was 3.410 mm,sensitivity was 0.767,specificity was 0.543.Conclusions:In the diagnosis of carotid atherosclerosis,the application of 3.0T high-resolution MRI imaging technology can accurately locate the plaque,and accurately measure the stenosis rate and the maximum wall thickness,the maximum length of the plaque,effectively judge the plaque surface fiber cap state and distinguish the internal components of the plaque,accurately identify the stability of the carotid plaque in patients with carotid atherosclerosis,and provide reference for the pathological development of patients with carotid atherosclerosis To provide accurate prediction and prognosis judgment has a very important guiding significance in the clinical treatment process.