scholarly journals Motion Estimation with Finite-Element Biomechanical Models and Tracking Constraints from Tagged MRI

2017 ◽  
pp. 81-90 ◽  
Author(s):  
Arnold D. Gomez ◽  
Fangxu Xing ◽  
Deva Chan ◽  
Dzung L. Pham ◽  
Philip Bayly ◽  
...  
Keyword(s):  
Finite Element ◽  
Motion Estimation ◽  
Tagged Mri ◽  
Biomechanical Models

scholarly journals SPINET: A Parallel Computing Approach to Spine Simulations

1996 ◽  
Vol 5 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Peter G. Kropf ◽  
Edgar F. A. Lederer ◽  
Thomas Steffen ◽  
Karl Guggisberg ◽  
Jean-Guy Schneider ◽  
...  
Keyword(s):  
Finite Element ◽  
Parallel Computing ◽  
Functional Programming ◽  
High Performance ◽  
Dynamic Models ◽  
Spinal Injury ◽  
Direct Method ◽  
Finite Element Program ◽  
Biomechanical Models ◽  
Interdisciplinary Approaches

Research in scientitic programming enables us to realize more and more complex applications, and on the other hand, application-driven demands on computing methods and power are continuously growing. Therefore, interdisciplinary approaches become more widely used. The interdisciplinary SPINET project presented in this article applies modern scientific computing tools to biomechanical simulations: parallel computing and symbolic and modern functional programming. The target application is the human spine. Simulations of the spine help us to investigate and better understand the mechanisms of back pain and spinal injury. Two approaches have been used: the first uses the finite element method for high-performance simulations of static biomechanical models, and the second generates a simulation developmenttool for experimenting with different dynamic models. A finite element program for static analysis has been parallelized for the MUSIC machine. To solve the sparse system of linear equations, a conjugate gradient solver (iterative method) and a frontal solver (direct method) have been implemented. The preprocessor required for the frontal solver is written in the modern functional programming language SML, the solver itself in C, thus exploiting the characteristic advantages of both functional and imperative programming. The speedup analysis of both solvers show very satisfactory results for this irregular problem. A mixed symbolic-numeric environment for rigid body system simulations is presented. It automatically generates C code from a problem specification expressed by the Lagrange formalism using Maple.

Initial Stress in Biomechanical Models of Atherosclerotic Plaques

2011 ◽  
Author(s):  
L. Speelman ◽  
A. C. Akyildiz ◽  
J. J. Wentzel ◽  
E. H. van Brummelen ◽  
J. Jukema ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Finite Element ◽  
Initial Stress ◽  
Atherosclerotic Plaque ◽  
Initial Stresses ◽  
Atherosclerotic Plaques ◽  
Finite Element Models ◽  
Biomechanical Models ◽  
Fibrous Cap ◽  
Stress Studies

Rupture of the cap of an atherosclerotic plaque is instigated when the stresses in the cap due to the blood pressure exceed the local cap strength. Image based computational finite element models of atherosclerotic plaques are widely used to compute stresses in the fibrous cap. These models are often based on pressurized geometries. The shape of the plaque is determined by the blood pressure at the time of imaging, and thus contains initial stresses (IS) and strains, which are generally ignored in plaque stress studies.

scholarly journals Finite element and deformation analyses predict pattern of bone failure in loaded zebrafish spines

2019 ◽  
Vol 16 (160) ◽  
pp. 20190430 ◽  
Author(s):  
Elis Newham ◽  
Erika Kague ◽  
Jessye A. Aggleton ◽  
Christianne Fernee ◽  
Kate Robson Brown ◽  
...  
Keyword(s):  
Finite Element ◽  
Disease Process ◽  
Intervertebral Discs ◽  
Vertebral Compression Fractures ◽  
Finite Element Models ◽  
Micro Computed Tomography ◽  
Spinal Motion ◽  
Biomechanical Models ◽  
Testing Stage ◽  
Ultimate Failure

The spine is the central skeletal support structure in vertebrates consisting of repeated units of bone, the vertebrae, separated by intervertebral discs (IVDs) that enable the movement of the spine. Spinal pathologies such as idiopathic back pain, vertebral compression fractures and IVD failure affect millions of people worldwide. Animal models can help us to understand the disease process, and zebrafish are increasingly used as they are highly genetically tractable, their spines are axially loaded like humans, and they show similar pathologies to humans during ageing. However, biomechanical models for the zebrafish are largely lacking. Here, we describe the results of loading intact zebrafish spinal motion segments on a material testing stage within a micro-computed tomography machine. We show that vertebrae and their arches show predictable patterns of deformation prior to their ultimate failure, in a pattern dependent on their position within the segment. We further show using geometric morphometrics which regions of the vertebra deform the most during loading, and that finite-element models of the trunk subjected reflect the real patterns of deformation and strain seen during loading and can therefore be used as a predictive model for biomechanical performance.

scholarly journals Cardiac motion estimation by joint alignment of tagged MRI sequences

2012 ◽  
Vol 16 (1) ◽  
pp. 339-350 ◽  
Author(s):  
E. Oubel ◽  
M. De Craene ◽  
A.O. Hero ◽  
A. Pourmorteza ◽  
M. Huguet ◽  
...  
Keyword(s):  
Motion Estimation ◽  
Cardiac Motion ◽  
Tagged Mri ◽  
Mri Sequences

Multiphase Poroelastic Finite Element Models for Soft Tissue Structures

1992 ◽  
Vol 45 (6) ◽  
pp. 191-218 ◽  
Author(s):  
Bruce R. Simon
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Material Behavior ◽  
Constitutive Law ◽  
Finite Strains ◽  
Finite Element Models ◽  
Tissue Fluid ◽  
Biomechanical Models ◽  
Highly Nonlinear ◽  
Tissue Structures

During the last two decades, biological structures with soft tissue components have been modeled using poroelastic or mixture-based constitutive laws, i.e., the material is viewed as a deformable (porous) solid matrix that is saturated by mobile tissue fluid. These structures exhibit a highly nonlinear, history-dependent material behavior; undergo finite strains; and may swell or shrink when tissue ionic concentrations are altered. Given the geometric and material complexity of soft tissue structures and that they are subjected to complicated initial and boundary conditions, finite element models (FEMs) have been very useful for quantitative structural analyses. This paper surveys recent applications of poroelastic and mixture-based theories and the associated FEMs for the study of the biomechanics of soft tissues, and indicates future directions for research in this area. Equivalent finite-strain poroelastic and mixture continuum biomechanical models are presented. Special attention is given to the identification of material properties using a porohyperelastic constitutive law and a total Lagrangian view for the formulation. The associated FEMs are then formulated to include this porohyperelastic material response and finite strains. Extensions of the theory are suggested in order to include inherent viscoelasticity, transport phenomena, and swelling in soft tissue structures. A number of biomechanical research areas are identified, and possible applications of the porohyperelastic and mixture-based FEMs are suggested.

scholarly journals Biomechanical analyses of Cambrian euarthropod limbs reveal their effectiveness in mastication and durophagy

2021 ◽  
Vol 288 (1943) ◽  
pp. 20202075
Author(s):  
Russell D. C. Bicknell ◽  
James D. Holmes ◽  
Gregory D. Edgecombe ◽  
Sarah R. Losso ◽  
Javier Ortega-Hernández ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Horseshoe Crab ◽  
Limulus Polyphemus ◽  
Arms Race ◽  
Trophic Relationships ◽  
Element Analysis ◽  
Biomechanical Models ◽  
Analysis Models ◽  
Key Innovations

Durophagy arose in the Cambrian and greatly influenced the diversification of biomineralized defensive structures throughout the Phanerozoic. Spinose gnathobases on protopodites of Cambrian euarthropod limbs are considered key innovations for shell-crushing, yet few studies have demonstrated their effectiveness with biomechanical models. Here we present finite-element analysis models of two Cambrian trilobites with prominent gnathobases— Redlichia rex and Olenoides serratus —and compare these to the protopodites of the Cambrian euarthropod Sidneyia inexpectans and the modern American horseshoe crab, Limulus polyphemus . Results show that L. polyphemus , S. inexpectans and R. rex have broadly similar microstrain patterns, reflecting effective durophagous abilities. Conversely, low microstrain values across the O. serratus protopodite suggest that the elongate gnathobasic spines transferred minimal strain, implying that this species was less well-adapted to masticate hard prey. These results confirm that Cambrian euarthropods with transversely elongate protopodites bearing short, robust gnathobasic spines were likely durophages. Comparatively, taxa with shorter protopodites armed with long spines, such as O. serratus , were more likely restricted to a soft food diet. The prevalence of Cambrian gnathobase-bearing euarthropods and their various feeding specializations may have accelerated the development of complex trophic relationships within early animal ecosystems, especially the ‘arms race' between predators and biomineralized prey.

Use of finite element method in 3D structure and motion estimation of nonrigid objects

2003 ◽  
Author(s):  
Themis Balomenos ◽  
Athanasios Drosopoulos ◽  
Amaryllis Raouzaiou ◽  
Kostas Karpouzis ◽  
Stefanos D. Kollias
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Motion Estimation ◽  
3D Structure ◽  
Structure And Motion ◽  
Structure And Motion Estimation ◽  
Element Method

Analytic signal phase-based myocardial motion estimation in tagged MRI sequences by a bilinear model and motion compensation

2015 ◽  
Vol 24 (1) ◽  
pp. 149-162 ◽  
Author(s):  
Liang Wang ◽  
Adrian Basarab ◽  
Patrick R. Girard ◽  
Pierre Croisille ◽  
Patrick Clarysse ◽  
...  
Keyword(s):  
Motion Estimation ◽  
Motion Compensation ◽  
Analytic Signal ◽  
Tagged Mri ◽  
Bilinear Model ◽  
Myocardial Motion ◽  
Signal Phase ◽  
Mri Sequences

scholarly journals Finite Element and deformation analyses predict pattern of bone failure in loaded zebrafish spines

2019 ◽  
Author(s):  
Elis Newman ◽  
Erika Kague ◽  
Jessye A. Aggleton ◽  
Christianne Fernee ◽  
Kate Robson Brown ◽  
...  
Keyword(s):  
Finite Element ◽  
Disease Process ◽  
Intervertebral Discs ◽  
Vertebral Compression Fractures ◽  
Finite Element Models ◽  
Micro Computed Tomography ◽  
Spinal Motion ◽  
Biomechanical Models ◽  
Testing Stage ◽  
Ultimate Failure

AbstractThe spine is the central skeletal support structure in vertebrates consisting of repeated units of bone, the vertebrae, separated by intervertebral discs that enable the movement of the spine. Spinal pathologies such as idiopathic back pain, vertebral compression fractures and intervertebral disc failure affect millions of people world-wide. Animal models can help us to understand the disease process, and zebrafish are increasingly used as they are highly genetically tractable, their spines are axially loaded like humans, and they show similar pathologies to humans during ageing. However biomechanical models for the zebrafish are largely lacking. Here we describe the results of loading intact zebrafish spinal motion segments on a material testing stage within a micro Computed Tomography machine. We show that vertebrae and their arches show predictable patterns of deformation prior to their ultimate failure, in a pattern dependent on their position within the segment. We further show using geometric morphometrics which regions of the vertebra deform the most during loading, and that Finite Element models of the trunk subjected reflect the real patterns of deformation and strain seen during loading and can therefore be used as a predictive model for biomechanical performance.

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