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Abdominal Aortic Aneurysm Dr. Andrea Bucchi School of Engineering – University of Portsmouth

Abdominal Aortic Aneurysm Dr. Andrea Bucchi School of Engineering – University of Portsmouth 9 th June 2014. University of Portsmouth – School of Engineering – Dr. Andrea Bucchi .

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Abdominal Aortic Aneurysm Dr. Andrea Bucchi School of Engineering – University of Portsmouth

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  1. Abdominal Aortic Aneurysm Dr. Andrea Bucchi School of Engineering – University of Portsmouth 9th June 2014 University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

  2. Abdominal aortic aneurysm (AAA) is ranked as 15th most frequent cause of death in individual aged over 60. It is responsible of 15000 deaths per year in US and 8000 in UK. AAA is asymptomatic and hence the patient is not aware of its presence. After the formation, during the years, aneurysm continues to grow typical at rate of 0.5–1.0 cm/year, until it reaches rupture. Associated mortality to AAA rupture is in the range 65-85%. University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

  3. NHS Abdominal Aortic Aneurysm Screening Programme for people aged 65 and over Current NHS approach is based on the multicentre aneurysm screening study (MASS) carried out by Alan Scott et collaborators. Main and only parameter taken into account is maximum aortic diameter: Aneurysm is defined if maximum diameter > 3cm. 3.0cm < Diameter < 4.4cm Monitoring every year. 4.4cm < Diameter < 5.5 cm Monitoring every 3 months. Diameter > 5.5 cm Endovascular repair needed. In literature are reported cases of aneurysm rupture with Diameter < 5.0 cm and other case of un-ruptured aneurysm with Diameter > 10 cm. University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

  4. Is it necessary to take into account other geometrical factors Shape, curvature, tortuosity, asymmetry, wall thickness, presence of calcifications…… How these effects can be explored? A database of different geometry can be explored to see the effects of the geometrical parameters on the determination of the Peak Wall Stress that appears a more realistic measure to assess risk of rupture. Georgakarakos et al. 2010 University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

  5. Create idealised geometry in Matlab and Mesh the arterial wall. Different shapes can be realised in Matlab changing the input file Mesh is exported in ABAQUS format [C3D8H element] University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

  6. Then the study needs to be applied on a real case. First problem when we are dealing with medical image obtained from a medical CT: The shape/geometry capture in the image is not pressure free. So a method is needed to recover the “pressure-free” configuration. This can be done iteratively (for example). University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

  7. Matlab invokes Abaqus as Solver Abaqus solves for displacements Matlab invokes Abaqus to run a Python script to extract displacements Matlab checks for convergence Matlab modifies the mesh Matlab takes care of file names University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

  8. Next steps: Optimize algorithm, reducing number of iterations needed to obtain the pressure-free configuration. Test the algorithm on medical images to see if it is enough robust. University of Portsmouth – School of Engineering – Dr. Andrea Bucchi

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