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Integrated geometric and mechanical analysis of an image-based lymphatic valve

Daniel J. Watson, Igor Sazonov Orcid Logo, David C. Zawieja, James E. Moore, Raoul van Loon Orcid Logo

Journal of Biomechanics, Volume: 64, Pages: 172 - 179

Swansea University Authors: Igor Sazonov Orcid Logo, Raoul van Loon Orcid Logo

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DOI (Published version): 10.1016/j.jbiomech.2017.09.040

Abstract

Lymphatic valves facilitate the lymphatic system’s role in maintaining fluid homeostasis. Malformed valves are found in several forms of primary lymphœdema, resulting in incurable swelling of the tissues and immune dysfunction. Their experimental study is complicated by their small size and operatio...

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Published in: Journal of Biomechanics
ISSN: 00219290
Published: 2017
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URI: https://cronfa.swan.ac.uk/Record/cronfa35694
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spelling 2020-07-14T14:24:51.5428719 v2 35694 2017-09-28 Integrated geometric and mechanical analysis of an image-based lymphatic valve 05a507952e26462561085fb6f62c8897 0000-0001-6685-2351 Igor Sazonov Igor Sazonov true false 880b30f90841a022f1e5bac32fb12193 0000-0003-3581-5827 Raoul van Loon Raoul van Loon true false 2017-09-28 AERO Lymphatic valves facilitate the lymphatic system’s role in maintaining fluid homeostasis. Malformed valves are found in several forms of primary lymphœdema, resulting in incurable swelling of the tissues and immune dysfunction. Their experimental study is complicated by their small size and operation in low pressure and low Reynolds number environments. Mathematical models of these structures can give insight and complement experimentation. In this work, we present the first valve geometry reconstructed from confocal imagery and used in the construction of a subject-specific model in a closing mode. A framework is proposed whereby an image is converted into a valve model. An FEA study was performed to identify the significance of the shear modulus, the consequences of smoothing the leaflet surface and the effect of wall motion on valve behaviour. Smoothing is inherent to any analysis from imagery. The nature of the image, segmentation and meshing all cause attenuation of high-frequency features. Smoothing not only causes loss of surface area but also the loss of high-frequency geometric features which may reduce stiffness. This work aimed to consider these effects and inform studies by taking a manual reconstruction and through manifold harmonic analysis, attenuating higher frequency features to replicate lower resolution images or lower degree-of-freedom reconstructions. In conclusion, two metrics were considered: trans-valvular pressure required to close the valve, ΔPc, and the retrograde volume displacement after closure. The higher ΔPc, the greater the volume of lymph that will pass through the valve during closure. Retrograde volume displacement after closure gives a metric of compliance of the valve and for the quality of the valve seal. In the case of the image-specific reconstructed valve, removing features with a wavelength longer than four μm caused changes in ΔPc. Varying the shear modulus from 10kPa to 60kPa caused a 3.85 fold increase in the retrograde volume displaced. The inclusion of a non-rigid wall caused ΔPc to increase from 1.56 to 2.52 cmH2O. Journal Article Journal of Biomechanics 64 172 179 00219290 Lymphatic; Valve; Harmonic manifold analysis; Segmentation; FEA 31 12 2017 2017-12-31 10.1016/j.jbiomech.2017.09.040 COLLEGE NANME Aerospace Engineering COLLEGE CODE AERO Swansea University 2020-07-14T14:24:51.5428719 2017-09-28T09:07:05.5846748 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Aerospace Engineering Daniel J. Watson 1 Igor Sazonov 0000-0001-6685-2351 2 David C. Zawieja 3 James E. Moore 4 Raoul van Loon 0000-0003-3581-5827 5 0035694-09102017091451.pdf watson2017.pdf 2017-10-09T09:14:51.8400000 Output 1371157 application/pdf Accepted Manuscript true 2018-10-07T00:00:00.0000000 true eng
title Integrated geometric and mechanical analysis of an image-based lymphatic valve
spellingShingle Integrated geometric and mechanical analysis of an image-based lymphatic valve
Igor Sazonov
Raoul van Loon
title_short Integrated geometric and mechanical analysis of an image-based lymphatic valve
title_full Integrated geometric and mechanical analysis of an image-based lymphatic valve
title_fullStr Integrated geometric and mechanical analysis of an image-based lymphatic valve
title_full_unstemmed Integrated geometric and mechanical analysis of an image-based lymphatic valve
title_sort Integrated geometric and mechanical analysis of an image-based lymphatic valve
author_id_str_mv 05a507952e26462561085fb6f62c8897
880b30f90841a022f1e5bac32fb12193
author_id_fullname_str_mv 05a507952e26462561085fb6f62c8897_***_Igor Sazonov
880b30f90841a022f1e5bac32fb12193_***_Raoul van Loon
author Igor Sazonov
Raoul van Loon
author2 Daniel J. Watson
Igor Sazonov
David C. Zawieja
James E. Moore
Raoul van Loon
format Journal article
container_title Journal of Biomechanics
container_volume 64
container_start_page 172
publishDate 2017
institution Swansea University
issn 00219290
doi_str_mv 10.1016/j.jbiomech.2017.09.040
college_str Faculty of Science and Engineering
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hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Aerospace Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Aerospace Engineering
document_store_str 1
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description Lymphatic valves facilitate the lymphatic system’s role in maintaining fluid homeostasis. Malformed valves are found in several forms of primary lymphœdema, resulting in incurable swelling of the tissues and immune dysfunction. Their experimental study is complicated by their small size and operation in low pressure and low Reynolds number environments. Mathematical models of these structures can give insight and complement experimentation. In this work, we present the first valve geometry reconstructed from confocal imagery and used in the construction of a subject-specific model in a closing mode. A framework is proposed whereby an image is converted into a valve model. An FEA study was performed to identify the significance of the shear modulus, the consequences of smoothing the leaflet surface and the effect of wall motion on valve behaviour. Smoothing is inherent to any analysis from imagery. The nature of the image, segmentation and meshing all cause attenuation of high-frequency features. Smoothing not only causes loss of surface area but also the loss of high-frequency geometric features which may reduce stiffness. This work aimed to consider these effects and inform studies by taking a manual reconstruction and through manifold harmonic analysis, attenuating higher frequency features to replicate lower resolution images or lower degree-of-freedom reconstructions. In conclusion, two metrics were considered: trans-valvular pressure required to close the valve, ΔPc, and the retrograde volume displacement after closure. The higher ΔPc, the greater the volume of lymph that will pass through the valve during closure. Retrograde volume displacement after closure gives a metric of compliance of the valve and for the quality of the valve seal. In the case of the image-specific reconstructed valve, removing features with a wavelength longer than four μm caused changes in ΔPc. Varying the shear modulus from 10kPa to 60kPa caused a 3.85 fold increase in the retrograde volume displaced. The inclusion of a non-rigid wall caused ΔPc to increase from 1.56 to 2.52 cmH2O.
published_date 2017-12-31T03:43:04Z
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score 10.938396

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