Carotid Intraplaque Hemorrhage Imaging Using MRI

Background Stroke is a chronic and non-communicable disease with high morbidity and mortality which brings serious social burden.Generally,the cause of ischemic stroke is atherosclerosis of large and medium systemic arteries,such as carotid artery.The rupture of carotid atherosclerotic plaques,secondary thrombosis,thrombosis falling off and thromboembolism may lead to ischemic stroke because of hypoperfusion.Early detection of vulnerable plaque and evaluation of its stability are helpful to monitor the disease and give reasonable and effective treatment.High resolution MRI is a non-invasive imaging method with high resolution of soft tissue and multi-sequence imaging which can provide information for the lesion area about overall anatomical features and different components of plaque,thus to evaluate plaque stability.Conventional scanning sequences are 3D TOF,T1 WI,T2WI,PDWI,CE-T1 WI,CE-MRA and so on.Recent studies have confirmed that 3D MPRAGE sequence can detect plaque hemorrhage with high sensitivity and specificity.Our study introduces a new magnetic resonance scanning sequence,3D Multi-contrast Atherosclerosis Characterization(MATCH),which can improve the limitations of traditional sequences in the diagnosis of carotid plaques.Taking histopathology as the gold standard,the purpose of this study is to evaluate the diagnostic performance of MATCH and MPRAGE were analyzed and compared.Objective The purpose of the work is to compare the diagnostic performance of MATCH and MPRAGE for the detection of IPH with histologic analysis as the reference standard.Methods Thirty individuals underwent 3T carotid MR imaging using MPRAGE,MATCH and 3D TOF with the diagnosis of carotid stenosis > 50% by ultrasound and scheduled for carotid endarterectomy from 2014 to 2015.Axial images cover all plaque centered at the bifurcation of the carotid artery.All image data sets were processed on semi-automatic software(MRI-Plaque View,VPDiagnostics,US)to analyze the component of IPH for vulnerable plaques.The consistency between MATCH and MPRAGE was analyzed by using Cohen kappa analysis;also analysis of the two sequences compared with pathology was analyzed in a similar manner.Calculating sensitivity and specificity of the two sequences compared with pathology.The SNR,CNR and Contrast Ratio(CR)of the two regions of interest are calculated.Results Among 30 patients,a total of 602 available sections and 95 matching histology specimens were included in the analysis.When all 602 available sections were included in the analysis,MATCH yielded good agreement with MPRAGE(?=0.773)on detecting IPH.With pathological specimens as the gold standard,moderate to good agreement was shown between MATCH and MPRAGE(?=0.778 vs.0.685).Sensitivity and specificity for the detection of IPH was 93.2%(68/73)and90.9%(20/22)for MATCH.For MPRAGE,sensitivity and specificity was87.7%(64/73)and 90.9%(20/22)respectively.Calculation of SNR,CNR and CR between the two sequences of ROI was as follows: SNR(80.5±67.0 vs.202.8±178.9,t=-12.2,P=0.00),CNR(103.2±88.6 vs.224.9±205.5,t=-10.1,P=0.00),CR(5.1±3.7 vs.1.3±0.9,t=22.6,P=0.00).Conclusion Compared to the MPRAGE sequence,MATCH technique demonstrates similar diagnostic performance for the detection of IPH.With the further development of imaging technology and the accumulation of clinical experience,MATCH has the potential to become a routine image examination to assess vulnerable plaques in clinical application.