title: Pubovisceralis Muscle Fiber Architecture Determination: Comparison Between Biomechanical Modeling and Diffusion Tensor Imaging.
abstract: Biomechanical analysis of pelvic floor dysfunction requires knowledge of certain biomechanical parameters, such as muscle fiber direction, in order to adequately model function. Magnetic resonance (MR) diffusion tensor imaging (DTI) provides an estimate of overall muscle fiber directionality based on the mathematical description of water diffusivity. This work aimed at evaluating the concurrence between pubovisceralis muscle fiber representations obtained from DTI, and the maximum principal stress lines obtained through the finite element method. Seven datasets from axial T2-weighted images were used to build numerical models, and muscle fiber orientation estimated from the DT images. The in-plane projections of the first eigenvector of both vector fields describing muscle fiber orientation were extracted and compared. The directional consistency was evaluated by calculating the angle between the normalized vectors for the entire muscle and also for the right and left insertions, middle portions, and anorectal area. The values varied between 28° ± 6 (right middle portion) and 34° ± 9 (anorectal area), and were higher than the angular precision of the DT estimates, evaluated using wild bootstrapping analysis. Angular dispersion ranged from 17° ± 4 (left middle portion) to 23° ± 5 (anorectal area). Further studies are needed to examine acceptability of these differences when integrating the vectors estimated from DTI in the numerical analysis.
authors.affiliation: Department of Radiology, Centro Hospitalar de São João - EPE, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal. sofia.brand@gmail.com.|Associated Laboratory for Energy, Transports and Aeronautics (LAETA), Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 400, 4200-465, Porto, Portugal. sofia.brand@gmail.com.
authors.forename: Sofia
authors.initials: S
authors.lastname: Brandão
authors.affiliation: Associated Laboratory for Energy, Transports and Aeronautics (LAETA), Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 400, 4200-465, Porto, Portugal.
authors.forename: Marco
authors.initials: M
authors.lastname: Parente
authors.affiliation: Associated Laboratory for Energy, Transports and Aeronautics (LAETA), Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 400, 4200-465, Porto, Portugal.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Silva
authors.affiliation: Associated Laboratory for Energy, Transports and Aeronautics (LAETA), Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 400, 4200-465, Porto, Portugal.|Biomechanics Laboratory, Center of Health and Sport Sciences, University of the State of Santa Catarina (CEFID/UDESC), Rua Pascoal Simone, 358, 88080-350, Florianópolis, Brazil.
authors.forename: Thuane
authors.initials: T
authors.lastname: Da Roza
authors.affiliation: Department of Obstetrics and Gynecology, Centro Hospitalar de São João - EPE, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Mascarenhas
authors.affiliation: Department of Radiology, Centro Hospitalar de Lisboa Norte-EPE - Hospital de Sta Maria, Faculty of Medicine, University of Lisbon, Avenida Prof. Egas Moniz, 1649-035, Lisbon, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Leitão
authors.affiliation: Department of Radiology, Centro Hospitalar de Lisboa Norte-EPE - Hospital de Sta Maria, Faculty of Medicine, University of Lisbon, Avenida Prof. Egas Moniz, 1649-035, Lisbon, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Cunha
authors.affiliation: Associated Laboratory for Energy, Transports and Aeronautics (LAETA), Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 400, 4200-465, Porto, Portugal.
authors.forename: Renato
authors.initials: R
authors.lastname: Natal Jorge
authors.affiliation: Instituto de Biofísica e Engenharia Biomédica (IBEB), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.|Department of Bioengineering and Institute for Systems and Robotics (ISR/IST), LARSyS, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisbon, Portugal.
authors.forename: Rita Gouveia
authors.initials: RG
authors.lastname: Nunes
mesh_terms: D000328:Adult; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008954:Models, Biological; D018485:Muscle Fibers, Skeletal; D017773:Pelvic Floor / Q000000981:diagnostic imaging*
keywords: Computational biomechanics; Finite element method; Magnetic resonance diffusion tensor imaging; Pelvic floor muscles