Dynamic contrast-enhanced MRI examination of atherosclerotic plaques: an animal study using rabbit model
10.3760/cma.j.issn.1005-1201.2011.08.015
- VernacularTitle:动态增强MRI技术评价动脉粥样斑块的实验研究
- Author:
Mingli LI
;
Jie SUN
;
Xiaoyan CHANG
;
Zhengyu JIN
- Publication Type:Journal Article
- Keywords:
Atherosclerosis;
Neovascularization;
Magnetic resonance imaging
- From:
Chinese Journal of Radiology
2011;45(8):770-774
- CountryChina
- Language:Chinese
-
Abstract:
Objective The enhanced patterns of atherosclerotic plaque on dynamic contrastenhanced MRI have not been well studied. The aim of this study was to explore the patterns of plaque enhancement and their underlying mechanism by using dynamic contrast-enhanced MRI (DCE-MRI).Methods Atherosclerotic plaques were induced in the aorta of 12 New Zealand White rabbits by a combination of endothelial denudation and high-cholesterol diet. Ten to sixteen weeks after surgery, DCEMRI was performed with a fast spin echo T1 weighted sequence. Thirty-five phases of images were obtained at 71-second intervals. Gd-DTPA was injected coincident with the third scan via marginal ear vein. Specimens were harvested within 12 hours after imaging for HE staining and CD31 immunohistochemical staining which was used to highlight nco-vessels. Plaque enhancement patterns were studied and compared with histological findings. Signal intensity of each plaque section was normalized to pre-contrast signal intensity of psoas muscle, after which signal intensity versus time curve was drawn. Pearson correlation coefficient was used to reveal association between histological neo-vessel count and descriptive parameters derived from signal intensity versus time curve. Results Plaques were significantly enhanced by Gd-DTPA. Enhancement patterns could be described as fast-in and slow-out. Differences in patterns of enhancement were observed between tissues, with fibrous tissue enhanced more than lipid aggregation and leukocyte foci. Peak enhancement( 1. 05 ±0. 30) , initial slope(0. 82 ± 0. 28 ) and area under the curve at early phase(4.97 ± 1.67) derived from signal intensity-time curve had significant correlations with neo-vessel count( 117.7 ± 93. 3) ( r= 0. 553,0. 468, 0. 554 respectively, P ＜ 0. 05 ) . Conclusions The enhanced patterns of atherosclerotic plaque by Gd-DTPA were fast- in and slow-out. Neovascularization, increased endothelial permeability and extracellular matrix may be the reasons for plaque enhancement by Gd-DTPA. DCE-MRI has the potential to quantify the extent of neo-vasculature formation within plaques.
