High Resolution MRI Study Of Vascular Remodeling Patterns And Related Factors In Patients With Middle Cerebral Artery Atherosclerosis

Part I Feasibility study of 3D-SPACE T1 WI enhanced sequence in comprehensive evaluation of atherosclerotic vessels in middle cerebral arteryObjective To explore the value of 3D-SPACE T1 WI enhancement sequence in the evaluation of involved vessels in patients with middle cerebral artery(MCA)atherosclerosis.Methods A total of 46 patients with unilateral middle cerebral artery(MCA)M1segment atherosclerotic stenosis or suspected stenosis were examined by HR-VWI,3D-TOF MRA and DSA before treatment.According to the examination mode,the patients were divided into DSA group,3D-TOF MRA group and 3D-SPACE T1 WI enhancement group.Taking the DSA group as the control group,the consistency of measuring lumen stenosis and lesion length between the other two groups and the DSA group was evaluated respectively.Result 3D-SPACE T1 WI enhancement is more consistent with DSA in evaluating the degree of lumen stenosis(ICC=0.91);compared with DSA,the degree of stenosis in3D-TOF MRA was higher(84.20 ± 19.26% vs.72.80 ± 16.02%,p< 0.001).Both3D-SPACE T1 WI enhancement and 3D-TOF MRA showed good consistency with DSA in evaluating the length of stenotic segment(ICC=0.92,ICC=0.87),but the measured results were higher than those of DSA(p< 0.001,p < 0.001).For suspected stenotic lesions on 3D-TOF MRA and DSA,plaques could still be accurately detected by3D-SPACE T1 WI enhancement.Conclusion 3D-SPACE T1 WI enhanced sequence is consistent with DSA in showing the degree of stenosis and the length of stenosis segment in MCA,and can provide non-invasive and accurate information of plaque in MCA,which is superior to3D-TOFMRA and DSA.It can be used as a routine non-invasive diagnosis and follow-up evaluation in patients with intracranial atherosclerosis.Part II Relationship between characteristics of atherosclerotic plaque and vascular remodeling in middle cerebral arteryObjective The purpose of this study is to explore the vascular remodeling patterns and related factors of middle cerebral artery(MCA)atherosclerosis based on3D-SPACE T1 WI enhancement sequence,focusing on the interpretation of remodeling from the perspective of plaque.Methods 92 patients with atherosclerotic plaque in MCA M1 segment were included.The vascular area and lumen area of the lesion were measured on the enhanced3D-SPACE T1 WI sequence,and the vascular area and lumen area at the reference point were measured.The wall area,plaque area,plaque burden,reconstruction index and so on were calculated.According to RI ≥ 1.05,0.95 < RI < 1.05 and RI ≤ 0.95,all patients were divided into three groups: positive remodeling group,intermediate remodeling group and negative remodeling group.The characteristics of vascular wall and plaque in the three groups were analyzed to explore the relevant factors affecting different remodeling patterns.Result Plaque quantitative analysis: LAMLN in NR group was lower than that in PR group(p< 0.001)and IR group(p< 0.001).The WAMLN of NR group was lower than that of PR group(p = 0.001).PA in PR group was higher than that in IR group(p= 0.002)and NR group(p< 0.001).In terms of plaque characteristics,there were significant differences in plaque distribution,plaque morphology and plaque enhancement among PR group,IR group and NR group(p< 0.001).The distribution of plaques in the NR group was mainly involved in the annular wall,and the occurrence rate of the annular wall in the NR group was significantly higher than that in the PR group(76.36% vs.10.53%,p< 0.001)and the IR group(76.36% vs.5.56%,p< 0.001).The eccentric plaque in PR group and IR group was higher than that in NR group(89.47% vs.23.64%,p< 0.001;94.44% vs.23.64%,p< 0.001,).In NR group,most of the plaques were in the shape of narrow concentric circles,and most of them were obviously enhanced.The results of multivariate Logistic regression analysis showed that plaque area(p<0.001),plaque burden(p=0.002),patch distribution(p<0.001)and plaque enhancement degree(p<0.001)were the important factors affecting the remodeling patterns of MCA M1 segment.Conclusion Negative remodeling is more common in patients with moderate and severe stenosis of middle cerebral artery atherosclerosis.The larger the plaque area,the more prone to positive remodeling;the plaques involving the vascular ring wall are more likely to appear negative remodeling;the incidence of narrow concentric plaques is higher in the negative remodeling group,and most of them are obviously enhanced.Plaque area,plaque burden,plaque distribution and plaque enhancement degree are the important factors affecting the vascular remodeling model of middle cerebral artery atherosclerosis.