| Background and objective:Carotid atherosclerosis is an important factor for ischemic cerebrovascular disease. Compared to the traditional method for predicting risk of stroke and making treatment programs which only depends on the degree of stenosis, quantitative analysis of plaque vulnerability including plaque burden and tissue components are more meaningful. Several studies have shown the high consistency between Magnetic Resonance Imaging(MRI) and in vivo pathology specimens of carotid plaque in measurement of plaque burden, manifestation of plaque tissue characteristics such as fibrous cap, lipid-rich necrotic core(LRNC),calcification and intraplaque hemorrhage(IPH).Taking MRI as the "gold standard", this study analyzed the plaque burden and tissue components by comparing three-dimensional ultrasound (3D-US)and MRI in order to assessing the clinical value of 3D-US in evaluating plaque vulnerability.Methods:1.　24 patients with carotid artery plaque enrolled undergone 3D-US and MRI within 48 hours with exclusion of those having the histories of carotid stenting, carotid endarterectomy, and coronary stenting. Images obtained by 3D-US and MRI were matched layer by layer, and 164 pairs of images were acquired.2. Correlation and consistency of lumen area (LA), wall area (WA), maximal wall thickness (MWT), and normalized wall index (NWI) acquired by 3D-US and MRI were analyzed by Pearson and Bland-Altman methods.3. For the plaque tissue analysis, gray-scale median(GSM)was obtained by 3D-US,with Vascular Plaque Quantification software(VPQ) and percentage of lipid-rich necrotic core(LRNC%)was obtained by MRI with CASCADE software. According to the plaque tissue components shown by MRI,164 pairs of images were divided into four groups including fiber group, lipid-rich core group, calcification group and complicated group, and the differences and 95%CI of GSM were compared among the groups.4. According to the carotid atherosclerosis score (CAS) system,164 pairs of images were divided into four groups from lowest-risk to highest-risk, and the differences of GSM among each group and 95%CI were analyzed.Results:1. For measurement of LA, WA, and MWT,3D-US and MRI had a good correlation(r=0.89,0.73,0.60, respectively), but a bad consistency. However, there was good correlation and consistency in measurement of NWI between 3D-US and MRI(r=0.75).2. GSM of the calcification group was the highest (95%CI:57.28～70.38) with significant difference from other groups whereas GSM of the lipid core group was the lowest (95%CI:41.79～49.36), but with no significance compared with the fiber group and complicated group.3. GSM of the highest-risk group was the lowest (95%CI:26.44～36.56), and there were significant differences among each group.Conclusions:With good correlation and consistency in NWI measurement and tissue components analysis with MRI,3D-US may be a more practical modality for predicting the rupture risk of vulnerable plaque. |
