Document Detail

Use of regional mechanical properties of abdominal aortic aneurysms to advance finite element modeling of rupture risk.
MedLine Citation:
PMID:  22313210     Owner:  NLM     Status:  In-Data-Review    
Abstract Purpose: To investigate the use of regional variations in the mechanical properties of abdominal aortic aneurysms (AAA) in finite element (FE) modeling of AAA rupture risk, which has heretofore assumed homogeneous mechanical tissue properties. Methods: Electrocardiogram-gated computed tomography scans from 3 male patients with known infrarenal AAA were used to characterize the behavior of the aneurysm in 4 different segments (posterior, anterior, and left and right lateral) at maximum diameter and above the infrarenal aorta. The elasticity of the aneurysm (circumferential cyclic strain, compliance, and the Hudetz incremental modulus) was calculated for each segment and the aneurysm as a whole. The FE analysis inclusive of prestress (pre-existing tensile stress) produced a detailed stress pattern on each of the aneurysm models under pressure loading. The 4 largest areas of stress in each region were considered in conjunction with the local regional properties of the segment to define a specific regional prestress rupture index (RPRI). Results: In terms of elasticity, there were average reductions of 68% in circumferential cyclic strain and 63% in compliance, with a >5-fold increase in incremental modulus, between the healthy and the aneurysmal aorta for each patient. There were also regional variations in all elastic properties in each individual patient. The average difference in total stress inclusive of prestress was 59%, 67%, and 15%, respectively, for the 3 patients. Comparing the strain from FE models with the CT scans revealed an average difference in strain of 1.55% for the segmented models and 3.61% for the homogeneous models, which suggests that the segmented models more accurately reflect in vivo behavior. RPRI values were calculated for each segment for all patients. Conclusion: A greater understanding of the local material properties and their use in FE models is essential for greater accuracy in rupture prediction. Quantifying the regional behavior will yield insight into the changes in patient-specific aneurysms and increase understanding about the progression of aneurysmal disease.
Aine P Tierney; Anthony Callanan; Timothy M McGloughlin
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of endovascular therapy : an official journal of the International Society of Endovascular Specialists     Volume:  19     ISSN:  1545-1550     ISO Abbreviation:  J. Endovasc. Ther.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-08     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100896915     Medline TA:  J Endovasc Ther     Country:  United States    
Other Details:
Languages:  eng     Pagination:  100-14     Citation Subset:  IM    
Materials and Surface Science Institute and the Centre for Applied Biomedical Engineering Research, Department of Mechanical, Aeronautical, and Biomedical Engineering, University of Limerick, Ireland.
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