Patient‐Specific Hemodynamic Analysis of Coronary Arteries

Abstract

In cases of severe cardiac stenosis, the selection of treatment options including angioplasty, stent insertion, and bypass surgery are based on cardiac diagnosis provided by electrocardiograms, stress tests, and angiograms. Although these diagnostic tools are all vital, it is still difficult to determine the true extent to which normal blood flow has been compromised. To date, a clear guideline for aggressive intervention does not exist, as stenosis characteristics can vary greatly between patients. Plaque composition, compressibility, and shape are all factors that can modify a patient's risk of incurring a life‐threatening cardiac event in the near future. Our work aims to establish a streamlined computational model that can provide accurate estimation of dynamic shear stress and tensile strain on a plaque based on a patient's specific geometry. Together with flow information provided by 4D cardiac MRI, information from the computational model will allow a cardiologist to make better informed decisions regarding therapeutic options for patient cardiac health.The goal of this undergraduate research project was to determine the most effective method for 3D reconstruction and segmentation of the heart and coronary arteries from patient‐specific CTA (computed tomography angiography) data. The resulting 3D geometry will be imported into COMSOL, a computational fluid dynamics software, for hemodynamics and stress‐strain analysis.Patients' CTA data was provided by the Cardiac Imaging Department of the St. Francis Hospital (with IRB approval). A set of 2097 images were imported into a 3D reconstruction software, 3D Slicer (http://www.slicer.org), and visualized in sagittal, axial, and coronal views. By scanning through images in each plane, major components of the heart (i.e., atria, ventricles, aorta, coronary arteries) were identified manually. 3D reconstruction and segmentation were accomplished using a seeding procedure in which each part of the heart was carefully selected and identified as an individual component. 3D Slicer then generated a 3D‐reconstructed geometry of the heart from seeds. Proper seeding allowed different components of the heart to be visualized individually in the 3D viewer, enabling isolation of the coronary arteries from the whole heart model.Preliminary results showed a 3D model of the whole heart from CTA data with the left main coronary isolated. Manual segmentation was found to be challenging because coronary artery branches are embedded within the cardiac muscle. It was demonstrated to be efficient to refine seeds for coronary artery identification and segmentation by carefully examining the 3D model and performing several iterations of correction. The coronary artery geometry generated in 3D Slicer is then processed by a Vascular Modeling Tool Kit (VMTK, an open source software) to generate the proper geometries (in .stl format) needed for COMSOL, for hemodynamics modeling and analysis.As methods for reconstruction and segmentation are further refined, computational modeling will be used as a high throughput tool to generate useful information on stress/strain conditions within the coronary arteries, moving toward our goal of streamlined personalized cardiac treatment.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.