Assessment of Plaque Stability Based on High-Resolution Magnetic Resonance Imaging of Human Atherosclerotic Lesions and Computational Mechanical Analysis

Abstract

Background-To date there is no efficient diagnostic strategy available for the assessment of plaque stability. The present work proposes a computational methodology to identify high-risk plaques. The proposed model considers eight major tissue components and allows three-dimensional mechanical analyses of plaque stability subject to various factors such as blood pressure and mechanical properties of tissue components. Methods and Results-Morphology of an eccentric low-grade lesion was determined by means of multi-phasic and highresolution magnetic resonance imaging on a 1.5 T whole body system and corresponding histological analyses. Nonlinear anisotropic material models were fitted to experimental data obtained from tensile tests of isolated tissue components. Stress distributions in the lesion were computed using nonlinear finite element analyses. Based on the particular low-grade lesion, the effects of elevated blood pressure were studied, and, additionally, the potential effects of changes in the lipid pool stiffness and the media stiffness, that can be controlled by drug treatment, investigated. Intimal stress distributions are strongly influenced by non-intimal components, and hence suitable modeling of non-intimal and intimal components is equally important. A meaningful stability assessment of individual lesions requires three-dimensional approaches. Conclusions-Realistic three-dimensional "morpho-mechanical" modeling of atherosclerotic lesions provide information and insights important for the assessment and understanding of plaque stability and related drug effects. This information can not be obtained by entirely morphological approaches.