title: Quantification of wall shear stress using a finite-element method in multidimensional phase-contrast MR data of the thoracic aorta.
abstract: We present a computational method for calculating the distribution of wall shear stress (WSS) in the aorta based on a velocity field obtained from two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI) data and a finite-element method. The WSS vector was obtained from a global least-squares stress-projection method. The method was benchmarked against the Womersley model, and the robustness was assessed by changing resolution, noise, and positioning of the vessel wall. To showcase the applicability of the method, we report the axial, circumferential and magnitude of the WSS using in-vivo data from five volunteers. Our results showed that WSS values obtained with our method were in good agreement with those obtained from the Womersley model. The results for the WSS contour means showed a systematic but decreasing bias when the pixel size was reduced. The proposed method proved to be robust to changes in noise level, and an incorrect position of the vessel wall showed large errors when the pixel size was decreased. In volunteers, the results obtained were in good agreement with those found in the literature. In summary, we have proposed a novel image-based computational method for the estimation of WSS on vessel sections with arbitrary cross-section geometry that is robust in the presence of noise and boundary misplacements.
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; Electrical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, Chile; Structural and Geotechnical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Julio
authors.initials: J
authors.lastname: Sotelo
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; Radiology Department, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Jesús
authors.initials: J
authors.lastname: Urbina
authors.affiliation: Pediatric Cardiology Unit, Hospital Virgen del Rocío, Seville, Spain; Laboratory of Cardiovascular Pathophysiology, Seville Biomedicine Institute, Hospital Virgen del Rocío, Seville, Spain.
authors.forename: Israel
authors.initials: I
authors.lastname: Valverde
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; Electrical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, Chile; Biological and Medical Engineering Institute, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Cristian
authors.initials: C
authors.lastname: Tejos
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; Electrical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, Chile; Biological and Medical Engineering Institute, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Irarrázaval
authors.affiliation: Structural and Geotechnical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, Chile; Biological and Medical Engineering Institute, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Hurtado
authors.affiliation: Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; Radiology Department, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile; Biological and Medical Engineering Institute, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Catolica de Chile, Santiago, Chile. Electronic address: suribe@med.puc.cl.
authors.forename: Sergio
authors.initials: S
authors.lastname: Uribe
mesh_terms: D000328:Adult; D001013:Aorta, Thoracic / Q000502:physiology; D001783:Blood Flow Velocity; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D013314:Stress, Mechanical; D055815:Young Adult
keywords: 2D CINE PC-MRI; Finite elements; Flow quantification; Fluid mechanics; Wall shear stress