The Value Of High-Resolution Magnetic Resonance Imaging In Middle Cerebral Arterial Stenosis Diseases

Part IThe Study of High-Resolution Magnetic Resonance Imaging for Middle Cerebral Arterial Stenosis in Young and Middle-agesBackground:Ischemic stroke is the leading cause of death and disability around the world.In our country,intracranial arterial stenosis is an important cause of ischemic stroke,especially in middle cerebral artery(MCA).There are many pathologies of middle cerebral arterial stenosis,including atherosclerosis,dissection,moyamoya disease,vasculitis etc.Dissection,moyamoya disease and vasculitis are supposed to be the most common pathologies in young adult.In recent years,along with our country people's living improvement and lifestyle changes,risk factors for vascular disease generally appear in advance,young people has increased incidence of atherosclerosis.So,the early clear of the causes in young and middle-aged patients with MCA stenosis is significant to choose a reasonable treatment method to prevent stroke.Objective:Our aim was to discuss feasibility of etiology diagnosis in the MCA stenosis using high resolution magnetic resonance technology through retrospectively analyzed the clinical and imaging data of the young and middle-aged patients with MCA stenosis.Methods:HRMRI examinations were performed on young and middle aged patients(18?years<55)diagnosed with moderate-to-severe MRA stenosis using MRA examination between October 2012 and December 2016.Comprehensive etiological diagnoses of MRA stenosis were conducted based on the patients' clinical and imaging data.Then,clinical and imaging characteristics of MRA stenosis caused by different etiologies(atherosclerosis,moyamoya disease,artery dissection and vasculitis,etc.)were analyzed retrospectively.Statistical analyses were conducted using SPSS for Windows(version 22.1,IBM SPSS,Chicago,IL).Differences in continuous variables were evaluated using single factor analysis of variance and independent sample t-test.The Fisher exact test or ?2 test was performed to assess the categorical variables,and the significance level was set at P<0.05.Comparisons of the numerical variables were tested using the LSD-t test.Result:(1)A total of 124 patients who with moderate-to-severe MRA stenosis(90 men,72.6%)were enrolled.The mean age was 41.5 ±9.02 years.High risk factors included hypertension(n = 74,59.7%),hyperlipidemia(n = 53,42.7%),cigarette smoking(n = 50,40.3%),diabetes mellitus(n = 19,15.3%).The pathologies of middle cerebral arterial stenosis,including atherosclerosis(n = 80,65.3%),dissection(n =16,12.9%),moyamoya disease(n =13,10.5%);vasculitis(n =15,11.3%).(2)Compared to the non-atherosclerotic stenosis group,the atherosclerotic stenosis group were older(P=0.001),had higher number of male(P=0.013),had a higher smoking rate(P=0.003),often showed the focal stenosis(P=0.000)in the middle section(P=0.049).The vessel outside diameters,maximal vessel wall thickness and eccentricity index at the maximal lumen narrowing were higher in the atherosclerotic stenosis group than these in the non-atherosclerotic stenosis group(P=0.000),the minimal vessel wall thickness were smaller in the atherosclerotic stenosis group than these in the non-atherosclerotic stenosis group(P=0.000).Additionally,the enhancement features between the atherosclerotic stenosis group and the non-atherosclerotic stenosis group had a significant difference(P=0.000).(3)Compared to the atherosclerotic stenosis group,the patients in dissection stenosis group often showed segmental stenosis(P=0.003),and they also had the smaller vessel outside diameters(P=0.001),maximal vessel wall thickness(P = 0.017)and eccentricity index(P=0.012)at the maximal lumen narrowing.The patients in vasculitis stenosis group were much younger(P=0.004),and often showed non-focal stenosis,ring-enhancement.Moyamoya disease stenosis were more common in females(P=0.009),and showed non-focal stenosis mostly,contralateral MCA were often involved(P=0.000).(4)The differences between dissection stenosis group and vasculitis stenosis group,moyamoya disease group in vessel outside diameters(P=0.001),maximal vessel wall thickness at the maximal lumen narrowing were significant(P<0.05).The significant differences were found between dissection stenosis group and moyamoya disease group in eccentricity index at the maximal lumen narrowing(P<0.05).Compared between the vasculitis stenosis group and the dissection stenosis group,the dissection stenosis group had a higher smoking rate(P=0.008),the patients in the vasculitis stenosis group often showed ring-enhancement(P=0.012).Compared with the moyamoya disease which involved in the proximal section of MCA in common,the dissection mostly involved in the middle and distal section of MCA(P=0.003).In addition,dissection stenosis were more common in one side of MCA,while contralateral MCA were also involved mostly among moyamoya disease stenosis(P=0.000).Similarly,compared with the vasculitis stenosis,contralateral MCA were often involved among moyamoya disease stenosis.(P=0.009).Conclusion:(1)Atherosclerosis was proposed the most common pathology of middle cerebral arterial stenosis among young and middle-aged patients besides dissection,moyamoya disease and vasculitis.(2)The atherosclerotic stenosis was more commonly found in elder males,who of them had a higher smoking rate.The atherosclerotic stenosis often showed focal stenosis and eccentricity enhancement in the middle section of MRA.In addition,the vessel outside diameters,maximal vessel wall thickness and eccentricity index at the maximal lumen narrowing were higher of the atherosclerotic stenosis than these of the non-atherosclerotic stenosis.(3)The non-atherosclerotic stenosis often showed non-focal stenosis and ring-enhancement.The patients in vasculitis stenosis group were much younger,and moyamoya disease stenosis are more common in females.(4)HR-MRI is helpful to etiological diagnosis of young and middle-aged patients with the MCA stenosis,and help us to understand the pathophysiology of the MCA stenosis more clearly.(5)Vasculitis and moyamoya disease have some overlapped HRMRI performance,when the performance is not typical,that need us to take combined the HRMRI performance with clinical,laboratory examination and follow-up to further determine the diagnoses.Part ?Age-Related Differences in High Resolution Magnetic Resonance Imaging Findings in Patients with Middle Cerebral Artery Atherosclerotic StenosisBackground:Coronary artery study has proved that age is related with remodeling pattern and plaque morphology,which will influence the selection of therapeutic regimen.However,the research on the relationship between change of intracranial atherosclerosis and age is limited.Recently,due to the development of HRMRI,it has been applied in research of intracranial artery and used to evaluate the intracranial atherosclerotic plaque morphology and remodeling pattern,which has good repeatability.Objectives:To assess the age-related differences in high resolution magnetic resonance imaging(HRMRI)findings of target lesions in patients with middle cerebral artery(MCA)atherosclerotic stenosis(?50%).Methods:We retrospectively reviewed high-resolution MRI for patients with MCA atherosclerotic stenosis(?50%)detected by MR angiography.Patients were grouped according to age:young group(?45 years)and old group(>45 years).The vessel area and lumen area were measured on the high resolution T1-weighted cross-sectional images at the maximal lumen narrowing(MLN)site and the reference site.Wall area,plaque size,the degree of stenosis,the percentage of plaque burden,and the remodeling index were calculated.Positive remodeling was defined as a remodeling index>1.0;Negative remodeling,as a remodeling<1.0.SPSS21.1(IBM,USA)software was applied to analyze the data.Measurement data complied with normal distribution,and was expressed as mean ± SD.The comparison between groups was analyzed by t test.Enumeration data was expressed as frequency and percentage.The comparison between groups was analyzed by x2 test and Fisher test.Interclass correlation coefficient and 95%confidence interval were used to evaluate the consistency between different measurer and different measurements by the same measurer.Results:(1)The repeatability of measurement between and in two groups on vessel area,lumen area,the thickest vessel thickness and the thinnest vessel thickness was very high.(2)Among 71 patients,young group included 24 patients(mean age 36.54 ± 5.72 years),while old group included 47 patients(mean age 57.49 ± 7.76 years).The gender between groups had no statistical significance,neither were DWI positive rate and symptomatic stenosis ratio.No matter in young group or middle-old group,hypertension was the most common risk factor,among which the morbidity in young group was 79.17%and in middle-old group was 78.72%without statistical significance.Smoking ratio in young group was 54.17%,which was significantly higher than that in middle-old group(29.79%).The morbidity of diabetes was 55.32%in middle-old group,which was significantly higher than that in young group(30.83%).Hyperlipidemia betweengroups had no statistical significance.(3)The incidence of negative remodeling in the young group was higher than the old group(55.32%vs 19.17%,p<0.05).The percentage of plaque burden in young group were smaller than old groups(0.314±0.183 vs 0.405±0.126,p<0.05).Conclusions:Remodeling pattern and plaque burden of MCA atherosclerotic stenosis were related with age.The negative remodeling ratio in young group was higher than that of old group,and the plaque burden percentage in young group was lower than old group.