IP029. Ultrasound Detection of Heterogeneous Accumulated Strain Within 3D Printed Patient Specific Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAA) are characterized by disturbed flow patterns, low and oscillatory wall shear stress with high gradients, increased particle residence time, and mild turbulence. Diameter is the most common metric for rupture prediction, although this metric can be unreliable. We hypothesize that understanding the flow topology and mixing inside AAA could provide useful insight into mechanisms of aneurysm growth. AAA morphology has high variability, as with AAA hemodynamics, and therefore we consider patient-specific analyses over several small to medium sized AAAs. Vortical patterns dominate AAA hemodynamics and traditional analyses based on the Eulerian fields (e.g. velocity) fail to convey the complex flow structures. The computation of finite-time Lyapunov exponent (FTLE) fields and underlying Lagrangian coherent structures (LCS) help reveal a Lagrangian template for quantifying the flow [1].

Download Full-text

Method for Incorporating Three-Dimensional Residual Stresses Into Patient-Specific Simulations of Arteries

Volume 1B: Extremity; Fluid Mechanics; Gait; Growth, Remodeling, and Repair; Heart Valves; Injury Biomechanics; Mechanotransduction and Sub-Cellular Biophysics; MultiScale Biotransport; Muscle, Tendon and Ligament; Musculoskeletal Devices; Multiscale Mechanics; Thermal Medicine; Ocular Biomechanics; Pediatric Hemodynamics; Pericellular Phenomena; Tissue Mechanics; Biotransport Design and Devices; Spine; Stent Device Hemodynamics; Vascular Solid Mechanics; Student Paper and Design Competitions ◽

10.1115/sbc2013-14232 ◽

2013 ◽

Author(s):

David M. Pierce ◽

Thomas E. Fastl ◽

Hannah Weisbecker ◽

Gerhard A. Holzapfel ◽

Borja Rodriguez-Vila ◽

...

Keyword(s):

Medical Imaging ◽

Three Dimensional ◽

Constitutive Models ◽

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Patient Specific ◽

Abdominal Aortic ◽

Model Geometry ◽

Reconstructed Model

Through progress in medical imaging, image analysis and finite element (FE) meshing tools it is now possible to extract patient-specific geometries from medical images of, e.g., abdominal aortic aneurysms (AAAs), and thus to study clinically relevant problems via FE simulations. Medical imaging is most often performed in vivo, and hence the reconstructed model geometry in the problem of interest will represent the in vivo state, e.g., the AAA at physiological blood pressure. However, classical continuum mechanics and FE methods assume that constitutive models and the corresponding simulations start from an unloaded, stress-free reference condition.

Download Full-text

Identification of rupture locations in patient-specific abdominal aortic aneurysms using experimental and computational techniques

Journal of Biomechanics ◽

10.1016/j.jbiomech.2009.09.057 ◽

2010 ◽

Vol 43 (7) ◽

pp. 1408-1416 ◽

Cited By ~ 50

Author(s):

Barry J. Doyle ◽

Aidan J. Cloonan ◽

Michael T. Walsh ◽

David A. Vorp ◽

Timothy M. McGloughlin

Keyword(s):

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Patient Specific ◽

Computational Techniques ◽

Abdominal Aortic

Download Full-text

Accessing 3D Printed Vascular Phantoms for Procedural Simulation

Frontiers in Surgery ◽

10.3389/fsurg.2020.626212 ◽

2021 ◽

Vol 7 ◽

Author(s):

Jasamine Coles-Black ◽

Damien Bolton ◽

Jason Chuen

Keyword(s):

3D Printing ◽

Endovascular Procedures ◽

Low Cost ◽

3D Models ◽

Routine Care ◽

Aortic Aneurysms ◽

Patient Specific ◽

Ct Angiogram ◽

Abdominal Aortic ◽

3D Printed

Introduction: 3D printed patient-specific vascular phantoms provide superior anatomical insights for simulating complex endovascular procedures. Currently, lack of exposure to the technology poses a barrier for adoption. We offer an accessible, low-cost guide to producing vascular anatomical models using routine CT angiography, open source software packages and a variety of 3D printing technologies.Methods: Although applicable to all vascular territories, we illustrate our methodology using Abdominal Aortic Aneurysms (AAAs) due to the strong interest in this area. CT aortograms acquired as part of routine care were converted to representative patient-specific 3D models, and then printed using a variety of 3D printing technologies to assess their material suitability as aortic phantoms. Depending on the technology, phantoms cost $20–$1,000 and were produced in 12–48 h. This technique was used to generate hollow 3D printed thoracoabdominal aortas visible under fluoroscopy.Results: 3D printed AAA phantoms were a valuable addition to standard CT angiogram reconstructions in the simulation of complex cases, such as short or very angulated necks, or for positioning fenestrations in juxtarenal aneurysms. Hollow flexible models were particularly useful for device selection and in planning of fenestrated EVAR. In addition, these models have demonstrated utility other settings, such as patient education and engagement, and trainee and anatomical education. Further study is required to establish a material with optimal cost, haptic and fluoroscopic fidelity.Conclusion: We share our experiences and methodology for developing inexpensive 3D printed vascular phantoms which despite material limitations, successfully mimic the procedural challenges encountered during live endovascular surgery. As the technology continues to improve, 3D printed vascular phantoms have the potential to disrupt how endovascular procedures are planned and taught.

Download Full-text

Predicting Patient-Specific Expansion of Abdominal Aortic Aneurysms

European Journal of Vascular and Endovascular Surgery ◽

10.1016/j.ejvs.2010.02.017 ◽

2010 ◽

Vol 40 (1) ◽

pp. 47-53 ◽

Cited By ~ 8

Author(s):

F. Helderman ◽

I.J. Manoch ◽

M. Breeuwer ◽

U. Kose ◽

H. Boersma ◽

...

Keyword(s):

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Patient Specific ◽

Abdominal Aortic ◽

Specific Expansion

Download Full-text

Flow-Induced Wall Pressure Under Average Resting Hemodynamic Conditions for Patient-Specific Abdominal Aortic Aneurysms

Advances in Bioengineering ◽

10.1115/imece2002-32326 ◽

2002 ◽

Author(s):

Ender A. Finol ◽

Shoreh Hajiloo ◽

Keyvan Keyhani ◽

David A. Vorp ◽

Cristina H. Amon

Keyword(s):

Imaging Techniques ◽

Abdominal Aortic Aneurysms ◽

Aneurysm Rupture ◽

Aortic Aneurysms ◽

Patient Specific ◽

Mortality And Morbidity ◽

Abdominal Aortic ◽

Lethal Event ◽

Overall Mortality

Abdominal Aortic Aneurysms (AAAs) are characterized by a continuous dilation of the infrarenal segment of the abdominal aorta. Despite significant improvements in surgical procedures and imaging techniques, the mortality and morbidity rates associated with untreated ruptured AAAs are still outrageously high. AAA disease is a health risk of significant importance since this kind of aneurysm is mostly asymptomatic until its rupture, which is frequently a lethal event with an overall mortality rate in the 80% to 90% range. From a purely biomechanical viewpoint, aneurysm rupture is a phenomenon that occurs when the mechanical stress acting on the dilating inner wall exceeds its failure strength. Since the internal mechanical forces are maintained by the dynamic action of blood flowing in the aorta, the quantification of the hemodynamics of AAAs is essential for the characterization of their biomechanical environment.

Download Full-text