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Micromechanical Characterization of Intra-luminal Thrombus Tissue from Abdominal Aortic Aneurysms
KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
Visa övriga samt affilieringar
2010 (Engelska)Ingår i: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 38, nr 2, s. 371-379Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The reliable assessment of Abdominal Aortic Aneurysm rupture risk is critically important in reducing related mortality without unnecessarily increasing the rate of elective repair. Intra-luminal thrombus (ILT) has multiple biomechanical and biochemical impacts on the underlying aneurysm wall and thrombus failure might be linked to aneurysm rupture. Histological slices from 7 ILTs were analyzed using a sequence of automatic image processing and feature analyzing steps. Derived microstructural data was used to define Representative Volume Elements (RVE), which in turn allowed the estimation of microscopic material properties using the non-linear Finite Element Method. ILT tissue exhibited complex microstructural arrangement with larger pores in the abluminal layer than in the luminal layer. The microstructure was isotropic in the abluminal layer, whereas pores started to orient along the circumferential direction towards the luminal site. ILT's macroscopic (reversible) deformability was supported by large pores in the microstructure and the inhomogeneous structure explains in part the radially changing macroscopic constitutive properties of ILT. Its microscopic properties decreased just slightly from the luminal to the abluminal layer. The present study provided novel microstructural and micromechanical data of ILT tissue, which is critically important to further explore the role of the ILT in aneurysm rupture. Data provided in this study allow an integration of structural information from medical imaging for example, to estimate ILT's macroscopic mechanical properties.

Ort, förlag, år, upplaga, sidor
2010. Vol. 38, nr 2, s. 371-379
Nyckelord [en]
Intra-luminal thrombus, Abdominal Aortic Aneurysm (AAA), Finite element, method (FEM), Microscale, Constitutive modeling, wall stress, rupture
Nationell ämneskategori
Medicinsk laboratorie- och mätteknik
Identifikatorer
URN: urn:nbn:se:kth:diva-19175DOI: 10.1007/s10439-009-9837-4ISI: 000274237000013Scopus ID: 2-s2.0-77249089737OAI: oai:DiVA.org:kth-19175DiVA, id: diva2:337222
Forskningsfinansiär
Vetenskapsrådet, 2006-7568
Anmärkning
QC 20110124Tillgänglig från: 2010-08-05 Skapad: 2010-08-05 Senast uppdaterad: 2017-12-12Bibliografiskt granskad
Ingår i avhandling
1. Multiscale Modeling of the Normal and Aneurysmatic Abdominal Aorta
Öppna denna publikation i ny flik eller fönster >>Multiscale Modeling of the Normal and Aneurysmatic Abdominal Aorta
2010 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
Ort, förlag, år, upplaga, sidor
Stockholm: KTH, 2010. s. 20
Serie
Trita-HFL. Rapport/ Institutionen för hållfasthetslära, KTH, ISSN 1654-1472 ; 0498
Identifikatorer
urn:nbn:se:kth:diva-28925 (URN)
Presentation
2010-12-20, Sal D3, Lindstedtsvägen 5, KTH, Stockholm, 10:15 (Engelska)
Opponent
Handledare
Anmärkning

QC 20110127

Tillgänglig från: 2011-01-27 Skapad: 2011-01-24 Senast uppdaterad: 2013-01-15Bibliografiskt granskad
2. Biomechanics of abdominal aortic aneurysm:Experimental evidence and multiscale constitutive modeling
Öppna denna publikation i ny flik eller fönster >>Biomechanics of abdominal aortic aneurysm:Experimental evidence and multiscale constitutive modeling
2012 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The reliable assessment of Abdominal Aortic Aneurysm (AAA) rupture risk is critically important in reducing related mortality without unnecessarily increasing the rate of elective repair. A multi-disciplinary approach including vascular biomechanics and constitutive modeling is needed to better understand and more effectively treat these diseases. AAAs are formed through irreversible pathological remodeling of the vascular wall and integrating this biological process in the constitutive description could improve the current understanding of this disease as well as the predictability of biomechanical simulations.

First in this thesis, multiple centerline-based diameter measurements between renal arteries and aortic bifurcation have been used to monitor aneurysm growth of in total 51 patients from Computer Tomography-Angiography (CT-A) data. Secondly, the thesis proposes a novel multi-scale constitutive model for the vascular wall, where collagen fibers are assembled by proteoglycan cross-linked collagen fibrils and reinforce an otherwise isotropic matrix (elastin). Collagen fibrils are dynamically formed by a continuous stretch-mediated process, deposited in the current configuration and removed by a constant degradation rate. The micro-plane concept is then used for the Finite Element (FE) implementation of the constitutive model. Finally, histological slices from intra-luminal thrombus (ILT) tissue were analyzed using a sequence of automatic image processing steps. Derived microstructural data were used to define Representative Volume Elements (RVEs), which in turn allowed the estimation of microscopic material properties using the non-linear FE.

The thesis showed that localized spots of fast diameter growth can be detected through multiple centerline-based diameter measurements all over the AAA sac. Consequently, this information might further reinforce the quality of aneurysm surveillance programs. The novel constitutive model proposed in the thesis has a strong biological motivation and provides an interface with biochemistry. Apart from modeling the tissue’s passive response, the presented model is helpful to predict saline feature of aneurysm growth and remodeling. Finally, the thesis provided novel microstructural and micromechanical data of ILT tissue, which is critically important to further explore the role of the ILT in aneurysm rupture.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2012. s. 48
Serie
Trita-HFL. Rapport/ Institutionen för hållfasthetslära, KTH, ISSN 1654-1472 ; 0530
Nationell ämneskategori
Maskinteknik Medicinteknik Materialteknik Teknisk mekanik
Identifikatorer
urn:nbn:se:kth:diva-101990 (URN)
Disputation
2012-09-20, Sal L1, Drottning Kristinas väg 30, KTH, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

QC 20120907

Tillgänglig från: 2012-09-07 Skapad: 2012-09-06 Senast uppdaterad: 2013-01-14Bibliografiskt granskad

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Gasser, T. ChristianMartufi, Giampaolo
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