title: A machine learning approach to investigate the relationship between shape features and numerically predicted risk of ascending aortic aneurysm.
abstract: Geometric features of the aorta are linked to patient risk of rupture in the clinical decision to electively repair an ascending aortic aneurysm (AsAA). Previous approaches have focused on relationship between intuitive geometric features (e.g., diameter and curvature) and wall stress. This work investigates the feasibility of a machine learning approach to establish the linkages between shape features and FEA-predicted AsAA rupture risk, and it may serve as a faster surrogate for FEA associated with long simulation time and numerical convergence issues. This method consists of four main steps: (1) constructing a statistical shape model (SSM) from clinical 3D CT images of AsAA patients; (2) generating a dataset of representative aneurysm shapes and obtaining FEA-predicted risk scores defined as systolic pressure divided by rupture pressure (rupture is determined by a threshold criterion); (3) establishing relationship between shape features and risk by using classifiers and regressors; and (4) evaluating such relationship in cross-validation. The results show that SSM parameters can be used as strong shape features to make predictions of risk scores consistent with FEA, which lead to an average risk classification accuracy of 95.58% by using support vector machine and an average regression error of 0.0332 by using support vector regression, while intuitive geometric features have relatively weak performance. Compared to FEA, this machine learning approach is magnitudes faster. In our future studies, material properties and inhomogeneous thickness will be incorporated into the models and learning algorithms, which may lead to a practical system for clinical applications.
authors.affiliation: Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206 387 Technology Circle, Atlanta, GA, 30313-2412, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Liang
authors.affiliation: Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206 387 Technology Circle, Atlanta, GA, 30313-2412, USA.
authors.forename: Minliang
authors.initials: M
authors.lastname: Liu
authors.affiliation: Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206 387 Technology Circle, Atlanta, GA, 30313-2412, USA.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Martin
authors.affiliation: Aortic Institute of Yale-New Haven Hospital, Yale University, New Haven, CT, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Elefteriades
authors.affiliation: Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206 387 Technology Circle, Atlanta, GA, 30313-2412, USA. wei.sun@bme.gatech.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
mesh_terms: D001014:Aortic Aneurysm / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003198:Computer Simulation; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D000069550:Machine Learning; D015233:Models, Statistical; D009716:Numerical Analysis, Computer-Assisted; D012044:Regression Analysis; D012306:Risk; D014057:Tomography, X-Ray Computed
keywords: Ascending aortic aneurysm; Computer-aided diagnosis; Finite element analysis; Machine learning