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4D-CT based motion analysis of a polymer-endograft combination after prophylactic sac filling, an in vitro study

Donker, Lianne (2023) 4D-CT based motion analysis of a polymer-endograft combination after prophylactic sac filling, an in vitro study.

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Embargo date:12 January 2029
Abstract:An aneurysm is an increase of diameter in a vein and can occur as a result of a weakened artery wall. This can lead to rupture of the vein, leading to an internal bleeding with a mortality rate of 80%. Surgical inter- vention can prevent rupture. For an abdominal aortic aneurysm (AAA), often endovascular repair (EVAR) is performed. In doing so, an endograft is inserted via the hip artery. Often, this prevents further enlarge- ment of the aneurysm sac and thus rupture. However, in 20% of the patients undergoing EVAR there is still bloodflow inside the AAA. This is called an endoleak. To prevent endoleaks, an upcoming technique ’active sac management’ can be applied. After placement of the endograft, a polymer will be inserted in the aneurysm sac to prevent any flow outside endograft. AneuFix is an example of a polymer that has been developed for this technique. However, inserting a sac filling poly- mer after EVAR might influence the diameter changes and displacements that occur during the cardiac cycle. Before EVAR, the diameter varies with 1 mm during a cardiac cycle and it displaces, in the cranial-caudal direction, with 1 mm or less per cycle. [1] After EVAR the pulsation in the diameter decreases to 1 mm or less [2] and the displacement decreases to approximately 1 mm. [3] The goals of this bachelor project was to investigate the influence of the polymer AneuFix on these movements after insertion in the aneurysm sac by use of an in vitro setup. For this an AAA phantom was used and 4D-CT scan, a ECG-gated CT scan, was made of the phantom with endograft before and after polymer insertion. This data was quantitatively analyzed for the displacement of the endograft and the maximal increase of the diameter during the cardiac cycle. Additionally, a qualitative analysis was used for internal movement. The results did not show that injection of the polymer AneuFix influences the pulsatile behaviour of the aortic wall or the endograft during the cardiac cycle, as there was no movement measured during the reference and the experimental measurement. This could have several causes, such as a resolution of CT scanner smaller than movement noted in literature, or a lower elasticity of the phantom compared to an abdominal aorta. However, after polymer insertion deformation of the phantom was noticed. These deformations probably were the result of the forces the polymer exerted on the phantom and endograft. In the total cranial-caudal direction there was an increase in length, although the phantom showed locally compression as well. In the transverse plane the AAA diameter in sagittal direction decreased. This is most likely due to compression of the polymer on the endograft. However, the endograft did not show a decreased diameter but an increased diameter instead. Therefore, it can be concluded that insertion of the polymer AneuFix influences the form of the phantom and exerts forces on the phantom and the endograft. However, based on this bachelor project, it cannot be determined that the polymer influences any movement of the endograft inside an AAA during the cardiac cylce.
Item Type:Essay (Bachelor)
Faculty:TNW: Science and Technology
Programme:Biomedical Technology BSc (56226)
Link to this item:https://purl.utwente.nl/essays/97950
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