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Celi S, Vignali E, Capellini K, Gasparotti E. On the Role and Effects of Uncertainties in Cardiovascular in silico Analyses. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:748908. [PMID: 35047960 PMCID: PMC8757785 DOI: 10.3389/fmedt.2021.748908] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/14/2021] [Indexed: 12/13/2022] Open
Abstract
The assessment of cardiovascular hemodynamics with computational techniques is establishing its fundamental contribution within the world of modern clinics. Great research interest was focused on the aortic vessel. The study of aortic flow, pressure, and stresses is at the basis of the understanding of complex pathologies such as aneurysms. Nevertheless, the computational approaches are still affected by sources of errors and uncertainties. These phenomena occur at different levels of the computational analysis, and they also strongly depend on the type of approach adopted. With the current study, the effect of error sources was characterized for an aortic case. In particular, the geometry of a patient-specific aorta structure was segmented at different phases of a cardiac cycle to be adopted in a computational analysis. Different levels of surface smoothing were imposed to define their influence on the numerical results. After this, three different simulation methods were imposed on the same geometry: a rigid wall computational fluid dynamics (CFD), a moving-wall CFD based on radial basis functions (RBF) CFD, and a fluid-structure interaction (FSI) simulation. The differences of the implemented methods were defined in terms of wall shear stress (WSS) analysis. In particular, for all the cases reported, the systolic WSS and the time-averaged WSS (TAWSS) were defined.
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Affiliation(s)
- Simona Celi
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Emanuele Vignali
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Katia Capellini
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Emanuele Gasparotti
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
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3
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Fanni BM, Sauvage E, Celi S, Norman W, Vignali E, Landini L, Schievano S, Positano V, Capelli C. A Proof of Concept of a Non-Invasive Image-Based Material Characterization Method for Enhanced Patient-Specific Computational Modeling. Cardiovasc Eng Technol 2020; 11:532-543. [PMID: 32748364 DOI: 10.1007/s13239-020-00479-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 07/22/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE Computational models of cardiovascular structures rely on their accurate mechanical characterization. A validated method able to infer the material properties of patient-specific large vessels is currently lacking. The aim of the present study is to present a technique starting from the flow-area (QA) method to retrieve basic material properties from magnetic resonance (MR) imaging. METHODS The proposed method was developed and tested, first, in silico and then in vitro. In silico, fluid-structure interaction (FSI) simulations of flow within a deformable pipe were run with varying elastic modules (E) between 0.5 and 32 MPa. The proposed QA-based formulation was assessed and modified based on the FSI results to retrieve E values. In vitro, a compliant phantom connected to a mock circulatory system was tested within MR scanning. Images of the phantom were acquired and post-processed according to the modified formulation to infer E of the phantom. Results of in vitro imaging assessment were verified against standard tensile test. RESULTS In silico results from FSI simulations were used to derive the correction factor to the original formulation based on the geometrical and material characteristics. In vitro, the modified QA-based equation estimated an average E = 0.51 MPa, 2% different from the E derived from tensile tests (i.e. E = 0.50 MPa). CONCLUSION This study presented promising results of an indirect and non-invasive method to establish elastic properties from solely MR images data, suggesting a potential image-based mechanical characterization of large blood vessels.
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Affiliation(s)
- B M Fanni
- BioCardioLab, Bioengineering Unit, Fondazione Toscana Gabriele Monasterio, Via Aurelia Sud, 54100, Massa, Italy.,Department of Information Engineering, University of Pisa, Via Girolamo Caruso 16, 56122, Pisa, Italy
| | - E Sauvage
- UCL Institute of Cardiovascular Science, 20c Guilford Street, London, WC1N 1DZ, UK.,Great Ormond Street Hospital for Children, NHS Foundation Trust, 30 Great Ormond Street, London, WC1N 3JH, UK
| | - S Celi
- BioCardioLab, Bioengineering Unit, Fondazione Toscana Gabriele Monasterio, Via Aurelia Sud, 54100, Massa, Italy.
| | - W Norman
- UCL Institute of Cardiovascular Science, 20c Guilford Street, London, WC1N 1DZ, UK.,Great Ormond Street Hospital for Children, NHS Foundation Trust, 30 Great Ormond Street, London, WC1N 3JH, UK
| | - E Vignali
- BioCardioLab, Bioengineering Unit, Fondazione Toscana Gabriele Monasterio, Via Aurelia Sud, 54100, Massa, Italy.,Department of Information Engineering, University of Pisa, Via Girolamo Caruso 16, 56122, Pisa, Italy
| | - L Landini
- BioCardioLab, Bioengineering Unit, Fondazione Toscana Gabriele Monasterio, Via Aurelia Sud, 54100, Massa, Italy.,Department of Information Engineering, University of Pisa, Via Girolamo Caruso 16, 56122, Pisa, Italy
| | - S Schievano
- UCL Institute of Cardiovascular Science, 20c Guilford Street, London, WC1N 1DZ, UK.,Great Ormond Street Hospital for Children, NHS Foundation Trust, 30 Great Ormond Street, London, WC1N 3JH, UK
| | - V Positano
- BioCardioLab, Bioengineering Unit, Fondazione Toscana Gabriele Monasterio, Via Aurelia Sud, 54100, Massa, Italy
| | - C Capelli
- UCL Institute of Cardiovascular Science, 20c Guilford Street, London, WC1N 1DZ, UK.,Great Ormond Street Hospital for Children, NHS Foundation Trust, 30 Great Ormond Street, London, WC1N 3JH, UK
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5
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Bosi GM, Capelli C, Cheang MH, Delahunty N, Mullen M, Taylor AM, Schievano S. Population-specific material properties of the implantation site for transcatheter aortic valve replacement finite element simulations. J Biomech 2018; 71:236-244. [PMID: 29482928 PMCID: PMC5889787 DOI: 10.1016/j.jbiomech.2018.02.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 02/07/2018] [Accepted: 02/09/2018] [Indexed: 10/31/2022]
Abstract
Patient-specific computational models are an established tool to support device development and test under clinically relevant boundary conditions. Potentially, such models could be used to aid the clinical decision-making process for percutaneous valve selection; however, their adoption in clinical practice is still limited to individual cases. To be fully informative, they should include patient-specific data on both anatomy and mechanics of the implantation site. In this work, fourteen patient-specific computational models for transcatheter aortic valve replacement (TAVR) with balloon-expandable Sapien XT devices were retrospectively developed to tune the material parameters of the implantation site mechanical model for the average TAVR population. Pre-procedural computed tomography (CT) images were post-processed to create the 3D patient-specific anatomy of the implantation site. Balloon valvuloplasty and device deployment were simulated with finite element (FE) analysis. Valve leaflets and aortic root were modelled as linear elastic materials, while calcification as elastoplastic. Material properties were initially selected from literature; then, a statistical analysis was designed to investigate the effect of each implantation site material parameter on the implanted stent diameter and thus identify the combination of material parameters for TAVR patients. These numerical models were validated against clinical data. The comparison between stent diameters measured from post-procedural fluoroscopy images and final computational results showed a mean difference of 2.5 ± 3.9%. Moreover, the numerical model detected the presence of paravalvular leakage (PVL) in 79% of cases, as assessed by post-TAVR echocardiographic examination. The final aim was to increase accuracy and reliability of such computational tools for prospective clinical applications.
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Affiliation(s)
- Giorgia M Bosi
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK; Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, London, UK.
| | - Claudio Capelli
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK
| | - Mun Hong Cheang
- Barts Health NHS Trust, University College London Hospital, London, UK
| | - Nicola Delahunty
- Barts Health NHS Trust, University College London Hospital, London, UK
| | - Michael Mullen
- Barts Health NHS Trust, University College London Hospital, London, UK
| | - Andrew M Taylor
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK
| | - Silvia Schievano
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK
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6
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Vukicevic M, Vekilov DP, Grande-Allen JK, Little SH. Patient-specific 3D Valve Modeling for Structural Intervention. STRUCTURAL HEART-THE JOURNAL OF THE HEART TEAM 2017. [DOI: 10.1080/24748706.2017.1377363] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Marija Vukicevic
- Department of Cardiology, Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Texas, USA
| | | | | | - Stephen H. Little
- Department of Cardiology, Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Texas, USA
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