Abstract
Intracranial aneurysms are balloon-shaped blobs on blood vessels inside the skull and are more brittle than the surrounding blood vessels, and can rupture, causing a stroke. To predict if an aneurysm is going to rupture, we are interested in the local blood flow inside the aneurysm. However, it is challenging to measure blood flow in the brain with good enough resolution. Progress in numerical simulations, combined with medical images of patients’ blood vessels, has provided new opportunities to model blood flow instead. However, the field has had several contentious areas, some of which could be attributed to the multitude of options and assumptions when performing such simulations. In this thesis I have therefore measured the real-world variability, going from a medical image to final blood flow simulation and rupture prediction, by comparing results across many research groups. I have also developed a new software tool that allows for parametric alteration of blood vessel geometry to study how it impacts blood flow. In medical image-based blood flow modeling for aneurysms, better reproducibility and replicability may help advance blood flow modeling as a robust research tool, which ultimately could assist clinicians in improving treatment strategy and patient outcomes.
List of papers
Paper I. Aslak W. Bergersen, Mikael Mortensen, and Kristian Valen-Sendstad ’The FDA nozzle benchmark: “In theory there is no difference between theory and practice, but in practice there is”’. In: Journal of Numerical Methods in Biomedical Engineering 35(1) (2019), DOI: 10.1002/cnm.3150. The article is included in the thesis. Also available at: https://doi.org/10.1002/cnm.3150 |
Paper II. Kristian Valen-Sendstad, Aslak W. Bergersen, Yuji Shimogonya et al. ’Real-world variability in the prediction of intracranial aneurysm wall shear stress: The 2015 international aneurysm CFD challenge’. In: Cardiovascular Engineering and Technology, 9(4) DOI: 10.1007/s13239-018-00374-2. The article is included in the thesis. Also available at: https://doi.org/10.1007/s13239-018-00374-2 |
Paper III. Aslak W. Bergersen, Christophe Chnafa, Diego Gallo, Marina Piccinelli, David A. Steinman, and Kristian Valen-Senstad ’Automated and objective removal of bifurcation aneurysms: incremental improvements, and validation against healthy controls.’. In: Journal of Biomechanics 96 (2019), DOI: 10.1016/j.jbiomech.2019.109342. The article is included in the thesis. Also available at: https://doi.org/10.1016/j.jbiomech.2019.109342 |
Paper IV. Aslak W. Bergersen, Henrik A. Kjeldsberg, and Kristian Valen-Sendstad ’A framework for automated and objective modification of tubular structures: Application to the internal carotid artery’. In International Journal of Numerical Methods in Biomedical Engineering 36(5) (2020), DOI: 10.1002/cnm.3330. The article is included in the thesis. Also available at: https://doi.org/10.1002/cnm.3330 |