Establishing the biomechanical properties of the pelvic soft tissues through an inverse finite element analysis using magnetic resonance imaging

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Silva, MET (Author) Other; Brandao, S (Author) Other; Parente, MPL (Author) FEUP; mascarenhas, t (Author) FMUP; Renato Natal Jorge (Author) FEUP

Journal

Title: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

Vol. 230

Pages: 298-309

ISSN: 0954-4119

Publisher: SAGE

Indexing

ISI Web of Knowledge - 17 Citations

Scopus - 21 Citations

Other information

Authenticus ID: P-00K-9X9

DOI: 10.1177/0954411916630571

Abstract (EN): The mechanical characteristics of the female pelvic floor are relevant when explaining pelvic dysfunction. The decreased elasticity of the tissue often causes inability to maintain urethral position, also leading to vaginal and rectal descend when coughing or defecating as a response to an increase in the internal abdominal pressure. These conditions can be associated with changes in the mechanical properties of the supportive structuresnamely, the pelvic floor musclesincluding impairment. In this work, we used an inverse finite element analysis to calculate the material constants for the passive mechanical behavior of the pelvic floor muscles. The numerical model of the pelvic floor muscles and bones was built from magnetic resonance axial images acquired at rest. Muscle deformation, simulating the Valsalva maneuver with a pressure of 4KPa, was compared with the muscle displacement obtained through additional dynamic magnetic resonance imaging. The difference in displacement was of 0.15mm in the antero-posterior direction and 3.69mm in the supero-inferior direction, equating to a percentage error of 7.0% and 16.9%, respectively. We obtained the shortest difference in the displacements using an iterative process that reached the material constants for the Mooney-Rivlin constitutive model (c(10)=11.8KPa and c(20)=5.53E-02KPa). For each iteration, the orthogonal distance between each node from the group of nodes which defined the puborectal muscle in the numerical model versus dynamic magnetic resonance imaging was computed. With the methodology used in this work, it was possible to obtain in vivo biomechanical properties of the pelvic floor muscles for a specific subject using input information acquired non-invasively.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12