Statin Use And High-resolution Magnetic Resonance Imaging Characteristic Of Intracranial Atherosclerosis Plaque

Purpose : Symptomatic intracranial atherosclerosis disease(SIACD)has high incidence and frequent recurrence,with the disability,cognitive impairment and depression increased,raising social and economic burdenglobally.Using HR-MRI,intracranial plaque characteristics including fibrous cap integrity,intra-plaque hemorrhage and plaque enhancement could be identified.However,quantitative analysis about vulnerable plaques is scarce.Statins are able to stabilize vulnerable plaque and reduce the risk of rupture,probably associating with plaque characteristics differentiated by HR-MRI.We are sought to study the vessel morphology,plaque characteristic and enhancement intensity between symptomatic and asymptomatic vessels using 3-dimensional high-resolution magnetic resonance imaging(HR-MRI),in order to explore the quantitative method of evaluating unstable plaques.In addition,we will divide subjects into groups according to premorbidstatin usage and compare the features of culprit plaques with non-culprit ones to evaluate the effect of statins.Method : Fifty-six patients who were suffered from SICAD are enrolled and underwent HR-MRI from April 2015 to March 2017.Two steps are performed to divide them into different groups.Firstly,all subjects are grouped into symptomatic and asymptomatic based on whether the stenotic vessel is culprit.Secondly symptomatic vessels are divided into non-statin usage and statin usage according to premorbid statins using.Measurements including lumen area(LA),outer wall area(OWA),signal intensity of plaques and so on were performed on professional software and relevant indices such as stenosis degree,plaque burden,enhancement index were calculated to evaluate the vulnerability of plaque.ROC analysis is used to compare different indices for evaluating the vulnerability of plaques.Comparison between non-statin usage and statin usage is performed to evaluate the effect of statins on plaque enhancement.Results: Compared with asymptomatic vessels,LA of symptomatic vessels was smaller and stenosis degree was more serious(P<0.05).The culprit plaques had higher signal intensity on T1 WI contrast imaging(390.74±122.00 vs 281.39±112.36,P=0.012)and EI based on reference wall(0.32±0.40 vs 0.04±0.23 P=0.031).Area under the curve(AUC)for post_SI_plaque and EI_ref is 0.729 and 0.741 respectively(95% confidence interval).The volume of plaque enhancement is significantly lower in statin usage(266.52±220.12 vs 111.17±89.90,P= 0.046).Conclusions:3D black blood HR-MRI can evaluatequantitatively the vulnerability of plaques.The measurements include LA,stenosis degree,plaque burden,post signal intensity and EI based on reference wall,which can help guide clinical diagnosis and prevention.Premorbid statin usage is associated with reduced volume of plaque enhancement in SICAD.