Application Of Dynamic Contrast-enhanced MR Imaging In Carotid Atherosclerotic Plaque

Objective:Carotid artery dynamic contrast-enhanced MRI?DCE-MRI?and MR vessel wall imaging?MR-VWI?were utilized to explore correlations between pharmacokinetic parameters of DCE-MRI?1?with plaque vulnerability and MRI-modified AHA classification;?2?with type 2 diabetes mellitus?T2DM?and glycosylated hemoglobin?HbA1c?;?3?with in-stent restenosis?ISR?.Materials and Methods:?1?From September 2015 to June 2016,66 patients with carotid intima thickening?2mm were included.All participants underwent MR-VVI and DCE-MRI.After plaques'classification according to MRI-modified AHA Lesion-Type?LT?,pharmacokinetic parameters?PPs?of DCE-MRI were measured,including K^trans,k_ep,v_e and v_p.Correlations between PPs and LTs and the ability of these parameters to distinguish stable and vulnerable plaques suspected on MRI were assessed.?2?From June 2016 to June 2017,57 patients with symptomatic carotid plaque were included.All participants underwent MR-VVI and DCE-MRI.Correlations between PPs of DCE-MRI with T2DM and HbA1c were analyzed by generalized linear regression model,in order to explore the effects of T2DM and blood glucose control on intraplaque inflammation and neovascularization.?3?From September 2015 to December 2017,40 patients who undergo the carotid artery stenting?CAS?were available for analysis.All participants underwent MR-VVI and DCE-MRI within one week before CAS.The position and stenosis of stent were re-examined by cerebral digital subtraction angiography?DSA?at the sixth month.Single and multivariate Logistic regression analysis was utilized to assess the correlation between DCE-MRI PPs and ISR.Results:?1?Significant positive correlation between K^transrans and LT ?I to VI was found??=0.532,P<0.001?,as was the correlation between k_epp and LT ?I to VI??=0.409,P<0.001?.Stable and vulnerable plaques suspected on MRI could potentially be distinguished by K^trans?sensitivity 83%,specificity 100%?and k_ep?sensitivity 77%,specificity 91%?.?2?The mean values of K^transrans and k_epp in T2DM group were significantly higher than those in non-T2DM group(0.097 min^-1±0.051 vs.0.060±0.032,p=0.004;1.658 min^-1±1.033vs.1.021±0.807,p=0.010).HbA1c level was independently associated with K^transrans among overall patients and T2DM patients??=0.434,P=0.002;?=0.439,P=0.024?.?3?The incidence rate of ISR was 20%.The mean values of K^transrans and k_epp in ISR group were significantly higher than those in non-ISR group(0.14 min^-1±0.04 vs.0.06±0.26,p=0.000;7.21 min^-1±4.35 vs.3.88±2.19,p=0.037).K^transrans could independently predict ISR?HR:1.12;95%CI:1.02¹.23;p=0.02?,with a cut-off value 0.09 min^-1?sensitivity100%,specificity 87.5%?.Conclusion:?1?K^transrans and k_epp from DCE-MRI can provide quantitative information to differentiate vulnerable plaques suspected on MRI from stable ones.These two parameters could be adopted as imaging biomarkers for plaque characterization and risk stratification.?2?T2DM and the levels of HbA1c play an important role in the development of inflammation and neovascularization in carotid plaque,further promoting the vulnerability of plaque.It is suggested that K^transrans combined with HbA1c level is of clinical value in assessing the risk of carotid plaque.?3?K^transrans could independently predict the risk of ISR with high sensitivity and specificity,which suggested that intraplaque inflammation may be involved in the pathological process of intimal restenosis after carotid stenting.DCE-MRI can be utilized as an effective tool to predict ISR.