Correlation Between Carotid Geometry And Middle Cerebral Artery Atherosclerosis

Objective Intracranial atherosclerosis is one of the main etiologies of ischemic stroke in China.Plenty of evidences have proved the artery geometry plays an irreplaceable role in the development of atherosclerosis.We aimed to investigate the correlation between carotid artery geometry and middle cerebral artery(MCA)atherosclerosis via 3-dimensional high-resolution magnetic resonance imaging(3D HRMRI),and to explore the impact of upstream artery geometry to distal atherosclerosis.Methods We reviewed our institutional head-neck combined HRMRI database,prospectively collected from May 2016 to September 2018,of patients suffered from stroke,vertigo and headache and acquired detailed imaging examination.Cases with internal carotid artery(ICA)occlusion,MCA occlusion or unclear image were excluded.After careful review of MCA walls,the cases enrolled were divided into plaque group and control group.Carotid artery and MCA geometries were examined in the participants,including carotid bifurcation angle,carotid bifurcation level,ICA/common carotid artery(CCA)lumen area ratio,shape of extracranial ICA,maximum curvature of extracranial ICA,intracranial ICA bending type and MCA bending direction.In the plaque group,the wall area of MCA cross section at the site of narrowest lumen was measured.The associations between carotid geometric parameters and the presence of MCA plaque were then analyzed.Results Two hundred and four units of ipsilateral carotid artery and MCA from 145 participants were eventually enrolled from 296 units of arteries analyzed.The plaque group contained 104 units of carotid artery and MCA while the control group contained 100.Compared with the artery units without MCA plaque,those with MCA plaque had a larger carotid artery bifurcation angle(55.82°vs.37.37°,p<0.0001),higher bifurcation level(p=0.009),more curved shape of extracranial ICA(p=0.008),and larger maximum curvature along extracranial ICA(116.15 m-1 vs.82.32 m-1,p=0.002).Other geometric features showed no difference between two groups.Binary logistic regression indicated that ICA/CCA lumen area ratio(odds ratio,1.455 per 0.1 increase;95%confidence interval,1.015-2.087)and carotid artery bifurcation angle(odds ratio,1.280 per 10-degree increase;95%confidence interval,1.058-1.548)were independently associated with MCA plaque formation after adjusting for the presence of extracranial ICA plaque,history of smoking,age,hypertension,diabetes mellitus,hyperlipidemia,other carotid geometric parameters and MCA curvature.In plaque group,the outer wall area,lumen area and wall area of MCA cross section at the site of narrowest lumen were 13.21±3.24 mm2?4.39±1.67 mm2,and 8.82±2.48 mm2 respectively.In multiply linear regression,the carotid bifurcation angle was linear correlated with the MCA wall area.Conclusion Among geometries of carotid artery,both ICA/CCA lumen area ratio and carotid bifurcation angle are independently associated with MCA atherosclerosis.The findings raise concerns about whether the development of intracranial atherosclerosis is influenced by the intraluminal hemodynamics of upstream vessels.