Abstract 11183: Three-Dimensional Finite Element Analysis of Atherosclerotic Plaque Rupture Based on ex vivo Cryo Imaging
Introduction: Cryo-imaging is an ex vivo vascular imaging modality that acquires serial 2D fluorescence and bright-field images at 5µm increments without sacrifice to tissue morphology. These features make cryo-imaging an attractive approach for rendering high-resolution 3D volumes that serve as a basis for finite element analysis (FEA) studies of plaque rupture. The current study utilizes images extracted from cryo imaging to render a 3D finite element model of a human coronary vessel to determine the stress and strain fields throughout an atherosclerotic plaque.
Methods: Fresh frozen specimens were sectioned and imaged. Nearly 630 image slices were processed and segmented using the specialized image processing software, ScanIP. Segmented regions included the fibrous cap, calcium, lipid, and the vessel wall. A 3D volume of the coronary vessel was rendered. FEA was performed under linear elastic conditions where material behavior was defined by two constants, Young’s modulus and Poisson’s ratio. Static load of human blood pressure ranging from 0-16 KPa was then applied along the luminal wall of the vessel.
Results: Figure 1 demonstrates the image segmentation process and results. Prior studies of human atherosclerotic materials have shown that the fibrous caps usually rupture when the material’s yield strength exceeds 300 KPa. The current model predicts an equivalent stress of 452 KPa which is 33% higher than the yield stress. The magnitude of the stress coupled with a cap thickness of ∼200 µm indicates a high likelihood of plaque rupture.
Conclusion: Cryo-imaging represents a novel ex vivo approach to rendering high resolution 3D volumes of coronary vessels. Being able to develop such accurate models via Cryo may serve as a valuable tool in order to further define vulnerable plaques. The current model is limited by the number of tissues segmented. Elastin and collagen are thought to be important contributors to plaque stability, and should be assessed in future studies.
- © 2012 by American Heart Association, Inc.