The Adrienne Hussey Scholarship was awarded to Jennifer Costelloe to allow her continue her research into the formation and rupture of cerebral aneurysms as part of her PhD in the University of Limerick. Since being award the Adrienne Hussey Scholarship, Jen presented her work at two Irish conferences, was awarded the best oral presentation at the University Hospital Limerick Research Symposium and has the huge honour of being invited to speak at the World Congress of Biomechanics in Boston in July 2015, which only takes place every 4 years. But don’t take our word for it, we’ll let Jen tell you about it herself!
After what seemed like a very long four years, I was delighted to finally submit and successfully defend my PhD thesis in January 2015. Although the road was quite challenging at times, I found the whole process incredibly rewarding. I can’t thank Friends of A and their supporters enough – I was so lucky to be awarded the Adrienne Hussey Scholarship which allowed me to progress my research and make valuable contributions to the field of cerebral aneurysm rupture risk.
The final title of my thesis was “Towards the Use of Geometric Parameters and Blood-Borne Species Concentration in the Prediction of Cerebral Aneurysm Growth and Rupture”. This might seem a little complicated, so to explain:
Cerebral aneurysms are swellings that are found at branching points or at curved arteries in the brain. One of the main issues with cerebral aneurysms is that we don’t know why they rupture, and the effects of rupture can be devastating – approximately 12% of patients die immediately, a further 40% die within one month and up to 30% of survivors are left with severe neurological defects. The exact mechanisms behind the formation, growth and rupture of aneurysms are unknown, and so a lot of recent research has focused on the aspects that contribute to rupture risk with the aim of preventing rupture before it occurs.
My thesis focused on three main aspects. Firstly, we investigated the differences between ruptured and unruptured aneurysms, to see if it’s possible that aspects of the shape and the geometry of the aneurysm might give an indication of its growth and rupture risk. Next, we focused on the hypothesis that the movement of different nutrients and species that are present in blood (like oxygen, nitric oxide, low density lipoproteins etc.) may have an effect on the wall of the aneurysm, causing it to weaken, grow and eventually rupture. Finally, we examined if there is a combined relationship between the different geometric features of aneurysms and the transport of blood-borne species with aneurysm growth and rupture potential. Using the results from the investigations carried out, we developed rupture risk equations that indicate the probability of an aneurysm rupturing. We then tested these equations on a set of aneurysm models, in order to determine their accuracy.
The main conclusions taken from the study were that the investigation into the relationship between geometric parameters and aneurysm rupture indicated that the odds of an aneurysm rupturing increase it is found in a posterior location within the brain, if it is bifurcating in shape, with increasing tilt angle and with increasing aspect ratio. For the combined relationship between geometric features and the transport of species in the blood, the rupture probability equation was able to correctly predict rupture in 70% of aneurysms. The results and conclusions found throughout the research have helped to increase our knowledge of the factors that influence cerebral aneurysm rupture potential and may aid in the development of improved aneurysm rupture risk assessment methods, ultimately improving clinical management of this devastating disease.