Contrast‐enhanced high resolution MRI for atherosclerotic carotid artery tissue characterization

Abstract

Purpose:To determine if a gadolinium-based contrast agent provides additional information for characterization of human plaque tissues, particularly neovasculature. Although high-resolution magnetic resonance imaging (MRI) has been used to identify plaque constituents in advanced atherosclerosis, some constituents, such as neovascularized tissue, defy detection. Materials and Methods:Non-contrast-enhanced carotid artery images from 18 patients scheduled for carotid endarterectomy and two normal volunteers were used to identify regions of fibrous tissue, necrotic core, or calcification, using established criteria. Then, the percent change in T1-weighted images after contrast enhancement was calculated for each region.Results: There were statistically significant differences in mean intensity change between tissues, with the largest increase for fibrous tissue (79.5%) and the smallest for necrotic core (28.6%). Additionally, histological analysis showed that a subset of fibrous regions rich in plaque neovascularization could be identified using a threshold of 80% enhancement (sensitivity ϭ 76%, specificity ϭ 79%). Conclusion:The ability of contrast-enhanced MRI to identify neovascularization and potentially improve differentiation of necrotic core from fibrous tissue further establishes MRI as a viable tool for in vivo study of atherosclerotic plaque.

Wash‐in kinetics for gadolinium‐enhanced magnetic resonance imaging of carotid atheroma

“…Enhancement of the fibrous cap after gadolinium administration is consistent with previously published observations (13,14). Interestingly, this study demonstrated enhancement of the lipid core; however, the mean enhancement of the cap was higher, for both absolute SI and SNR, than the mean enhancement of the core at each period and overall.…”

“…Wasserman et al (13) showed that the use of a gadoliniumbased contrast agent helped discriminate the fibrous cap from the lipid core with a contrast-to-noise ratio (CNR) as good as or better than that with T2-weighted MR images, but with approximately twice the signal-tonoise ratio (SNR). Yuan et al (14) reported similar results. Although the contrast agent penetrated both the fibrous cap and lipid core, both studies found that there was preferential uptake of the contrast agent into the fibrous tissue.…”

Imaging of the Carotid Artery Vulnerable Plaque

“…Different contrast agents are currently used to characterize carotid plaque. Gadolinium-chelates contrast agents are most commonly used for MRA examinations; for the assessment of unstable plaques, the vascular enhancement of the carotid plaques themselves has been demonstrated to hallmark the presence of an increased endothelial permeability due to plaque inflammation that facilitates the entry of contrast agents [83,[91][92][93][94][95].…”

Comparative study into the robustness of compartmental modeling and model‐free analysis in DCE‐MRI studies

“…4 and references therein), multiple sclerosis (5), rheumatoid arthritis (6), atherosclerosis (7,8), Crohn's disease (9) and other inflammatory conditions (10), and are potentially able to provide information concerning the blood volume of the tissue, microvessel permeability, and lesion interstitial space. These parameters may be extracted from a DCE-MRI time course via the application of models that describe the distribution of contrast agent in vivo.…”