An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms
(1) Abdominal aortic aneurysm (AAA) biomechanics-based metrics often reported may be over/under-estimated by including non-aneurysmal regions in the analyses, which is typical, rather than isolating the dilated sac region. We demonstrate the utility of a novel sac-isolation algorithm by comparing pe...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Bioengineering |
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| Online Access: | https://www.mdpi.com/2306-5354/9/11/601 |
| _version_ | 1797469044284063744 |
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| author | Timothy K. Chung Pete H. Gueldner Trevor M. Kickliter Nathan L. Liang David A. Vorp |
| author_facet | Timothy K. Chung Pete H. Gueldner Trevor M. Kickliter Nathan L. Liang David A. Vorp |
| author_sort | Timothy K. Chung |
| collection | DOAJ |
| description | (1) Abdominal aortic aneurysm (AAA) biomechanics-based metrics often reported may be over/under-estimated by including non-aneurysmal regions in the analyses, which is typical, rather than isolating the dilated sac region. We demonstrate the utility of a novel sac-isolation algorithm by comparing peak/mean wall stress (PWS, MWS), with/without sac isolation, for AAA that were categorized as stable or unstable in 245 patient CT image sets. (2) 245 patient computed tomography images were collected, segmented, meshed, and had subsequent finite element analysis performed in preparation of our novel sac isolation technique. Sac isolation was initiated by rotating 3D surfaces incrementally, extracting 2D projections, curve fitting a Fourier series, and taking the local extrema as superior/inferior boundaries for the aneurysmal sac. The PWS/MWS were compared pairwise using the entire aneurysm and the isolated sac alone. (3) MWS, not PWS, was significantly different between the sac alone and the entire aneurysm. We found no statistically significant difference in wall stress measures between stable (<i>n</i> = 222) and unstable (<i>n</i> = 23) groups using the entire aneurysm. However, using sac-isolation, PWS (24.6 ± 7.06 vs. 20.5 ± 8.04 N/cm<sup>2</sup>; <i>p</i> = 0.003) and MWS (12.0 ± 3.63 vs. 10.5 ± 4.11 N/cm<sup>2</sup>; <i>p</i> = 0.022) were both significantly higher in unstable vs. stable groups. (4) Our results suggest that evaluating only the AAA sac can influence wall stress metrics and may reveal differences in stable and unstable groups of aneurysms that may not otherwise be detected when the entire aneurysm is used. |
| first_indexed | 2024-03-09T19:15:52Z |
| format | Article |
| id | doaj.art-1cf8d801df7d45dbae43775f46e9920b |
| institution | Directory Open Access Journal |
| issn | 2306-5354 |
| language | English |
| last_indexed | 2024-03-09T19:15:52Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Bioengineering |
| spelling | doaj.art-1cf8d801df7d45dbae43775f46e9920b2023-11-24T03:45:52ZengMDPI AGBioengineering2306-53542022-10-0191160110.3390/bioengineering9110601An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic AneurysmsTimothy K. Chung0Pete H. Gueldner1Trevor M. Kickliter2Nathan L. Liang3David A. Vorp4Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USADepartment of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USADepartment of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USADepartment of Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USADepartment of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA(1) Abdominal aortic aneurysm (AAA) biomechanics-based metrics often reported may be over/under-estimated by including non-aneurysmal regions in the analyses, which is typical, rather than isolating the dilated sac region. We demonstrate the utility of a novel sac-isolation algorithm by comparing peak/mean wall stress (PWS, MWS), with/without sac isolation, for AAA that were categorized as stable or unstable in 245 patient CT image sets. (2) 245 patient computed tomography images were collected, segmented, meshed, and had subsequent finite element analysis performed in preparation of our novel sac isolation technique. Sac isolation was initiated by rotating 3D surfaces incrementally, extracting 2D projections, curve fitting a Fourier series, and taking the local extrema as superior/inferior boundaries for the aneurysmal sac. The PWS/MWS were compared pairwise using the entire aneurysm and the isolated sac alone. (3) MWS, not PWS, was significantly different between the sac alone and the entire aneurysm. We found no statistically significant difference in wall stress measures between stable (<i>n</i> = 222) and unstable (<i>n</i> = 23) groups using the entire aneurysm. However, using sac-isolation, PWS (24.6 ± 7.06 vs. 20.5 ± 8.04 N/cm<sup>2</sup>; <i>p</i> = 0.003) and MWS (12.0 ± 3.63 vs. 10.5 ± 4.11 N/cm<sup>2</sup>; <i>p</i> = 0.022) were both significantly higher in unstable vs. stable groups. (4) Our results suggest that evaluating only the AAA sac can influence wall stress metrics and may reveal differences in stable and unstable groups of aneurysms that may not otherwise be detected when the entire aneurysm is used.https://www.mdpi.com/2306-5354/9/11/601abdominal aortic aneurysmsac isolationfinite element analysisbiomechanics |
| spellingShingle | Timothy K. Chung Pete H. Gueldner Trevor M. Kickliter Nathan L. Liang David A. Vorp An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms Bioengineering abdominal aortic aneurysm sac isolation finite element analysis biomechanics |
| title | An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms |
| title_full | An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms |
| title_fullStr | An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms |
| title_full_unstemmed | An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms |
| title_short | An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms |
| title_sort | objective and repeatable sac isolation technique for comparing biomechanical metrics in abdominal aortic aneurysms |
| topic | abdominal aortic aneurysm sac isolation finite element analysis biomechanics |
| url | https://www.mdpi.com/2306-5354/9/11/601 |
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