Title: Image-based mechanical analysis of stent deformation : concept and exemplary implementation for aortic valve stents
Authors : Gessat, Michael
Hopf, Raoul
Pollok, Thomas
Russ, Christoph
Frauenfelder, Thomas
Sundermann, Simon Harald
Hirsch, Sven
Mazza, Edoardo
Szekely, Gabor
Falk, Volkmar
Published in : IEEE Transactions on Biomedical Engineering
Volume(Issue) : 61
Issue : 1
Pages : 4
Pages to: 15
Publisher / Ed. Institution : IEEE
Issue Date: 2014
License (according to publishing contract) : Licence according to publishing contract
Type of review: Peer review (Publication)
Language : English
Subjects : Biomedical simulation; Stent placement; Calcinosis; Finite element analysis; Heart valve prosthesis implantation; Prosthesis design
Subject (DDC) : 610: Medicine and health
617: Surgery
Abstract: An approach for extracting the radial force load on an implanted stent from medical images is proposed. To exemplify the approach, a system is presented which computes a radial force estimation from computer tomography images acquired from patients who underwent transcatheter aortic valve implantation (TAVI). The deformed shape of the implanted valve prosthesis' Nitinol frame is extracted from the images. A set of displacement vectors is computed that parameterizes the observed deformation. An iterative relaxation algorithm is employed to adapt the information extracted from the images to a finite-element model of the stent, and the radial components of the interaction forces between the stent and the tissue are extracted. For the evaluation of the method, tests were run using the clinical data from 21 patients. Stent modeling and extraction of the radial forces were successful in 18 cases. Synthetic test cases were generated, in addition, for assessing the sensitivity to the measurement errors. In a sensitivity analysis, the geometric error of the stent reconstruction was below 0.3 mm, which is below the image resolution. The distribution of the radial forces was qualitatively and quantitatively reasonable. An uncertainty remains in the quantitative evaluation of the radial forces due to the uncertainty in defining a radial direction on the deformed stent. With our approach, the mechanical situation of TAVI stents after the implantation can be studied in vivo, which may help to understand the mechanisms that lead to the complications and improve stent design.
Departement: Life Sciences und Facility Management
Organisational Unit: Institute of Applied Simulation (IAS)
Publication type: Article in scientific Journal
DOI : 10.1109/TBME.2013.2273496
ISSN: 0018-9294
1558-2531
URI: https://digitalcollection.zhaw.ch/handle/11475/13619
Appears in Collections:Publikationen Life Sciences und Facility Management

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