A Study On The Characteristics Of Intracranial Vascular Wall Plaques In Patients With Ischemic Stroke On High-Resolution MRI

Objective:To investigate the distribution characteristics of plaques in the middle cerebral artery(MCA)stenosis and basilar artery(BA)stenosis on 3.0T high-resolution magnetic resonance imaging(HR-MRI).Methods:78 ischemic stroke patients with the middle cerebral artery(MCA)stenosis or basilar artery(BA)stenosis were collected from July 2018 to August 2019 in the Department of Neurology,the second hospital of Hebei Medical University.All patients underwent conventional magnetic resonance imaging(including Diffusion weighted imaging,DWI and Magnetic Resonance Angiography,MRA)and HR-MRI examinations.All MRI images were measured by experienced radiologists using Vessel Explorer which is a software for plaque analysis.General clinical datas and Related hematological indexes were collected.Plaques with vascular stenosis were divided into four groups:the group of middle cerebral artery(MCA)and the basilar artery(BA),the group of responsible plaques and non-responsible plaques,the group of positive remodeling(PR)and the negative remodeling(NR),the group of 30%-50% mild stenosis,50%-70% moderate stenosis and 70%-90% severe stenosis.The measurement and analysis indicators are as follows.(1)Based on TIW1-VISTA images,we measured and calculated the vascular parameters at the narrowest part of blood vessels(including outer wall areas,wall areas,lumen areas,the maximum/Minimum wall thickness,the plaque load,the remodeling rate,the eccentricity index,the stenosis rate,the plaque enhancement,the plaque morphology),and measured the outer wall areas,wall areas and lumen areas at the reference site of blood vessels.(2)We compared the general clinical datas,hematological indexes and vascular parameter indicators between MCA and BA group.(3)We compared the vascular parameters between the responsible plaques and the non-responsible plaques,compared the vascular parameters between the positive remodeling(PR)group and the negative remodeling(NR)group,and compared the vascular parameters of mild stenosis group,moderate stenosis group and severe stenosis group.Results:A total of 75 patients were included and 86 plaques were analyzed.Patients in the middle cerebral artery(MCA)plaques and basilar artery(BA)plaques group had no statistical significance between vascular risk factors,hematological indicators,and NIHSS scores(P>0.05),which had statistical significance in plaque loads(P<0.001),and there was no statistically significant differences in other indicators(P>0.05).The responsible plaques and the non-responsive plaques of BA group were statistically significant between the wall areas,lumen areas,stenosis rates,and plaque enhancement(P<0.001,P<0.001,P<0.001,P=0.002),The other indicators were not statistically significant(P>0.05).The responsible plaques and the non-responsive plaques of MCA group were statistically significant between the wall areas,lumen areas,plaque loads and stenosis rates(P=0.004,P=0.013,P=0.016,P=0.032).The other indicators has no statistical significances(P> 0.05).The vascular parameters and NIHSS scores of responsible plaques in MCA group and BA group were not statistically significant(P>0.05).The positive remodeling(PR)group and negative remodeling(NR)group have statistically significances between the outer wall areas,the wall areas,the plaque loads,and the stenosis rates(P=0.008,P=0.045,P=0.002,P=0.018),the other indicators have no statistical significances(P>0.05).The mild stenosis group(30%-50%)and the severe stenosis group(70%-90%)had statistical differences in remodeling rate and remodeling modes(P=0.005,P= 0.013).Conclusions:(1)arteries of Positive remodeling have larger vascular outer wall areas,wall areas and plaque loads,and the degree of stenosis is lighter;(2)The higher the degree of vascular stenosis,the more likely the fibrosis and thickening of the adventitia of the blood vessel will limit the outward expansion of the outer wall,and the remodeling pattern tends to be non-positive remodeling;(3)The responsible plaques have larger wall areas and higher vessel stenosis rate,Most of the responsible plaques of basilar artery are obviously strengthened plaques.Most of the non-responsible plaques are non-/mildly enhanced plaques.(4)There is no fixed morphological feature between responsible and non-responsible plaques in the middle cerebral artery and basilar artery.