M. Graña Romay et al. (Eds.): HAIS 2010, Part I, LNAI 6076, pp. 524–531, 2010. © Springer-Verlag Berlin Heidelberg 2010 Thrombus Volume Change Visualization after Endovascular Abdominal Aortic Aneurysm Repair Josu Maiora 1,4 , Guillermo García 2 , Iván Macía 3,4 , Jon Haitz Legarreta 3 , Fernando Boto 3 , Céline Paloc 3 , Manuel Graña 4 , and Javier Sanchez Abuín 5 1 Electronics and Telecomunications Department, 2 Engineering Systems and Automatic Department, Technical University School, University of the Basque Country, Donostia-San Sebastián, Spain {j.maiora,g.garcia}@ehu.es 3 eHealth and Biomedical Applications Department, Vicomtech, Donostia-San Sebastián, Spain {imacia,jhlegarreta,fboto,cpaloc}@vicomtech.org 4 Computational Intelligence Group, Computer Science Faculty, University of the Basque Country, Donostia-SanSebastián, Spain manuel.grana@ehu.es 5 Interventional Radiology Service, Donostia Hospital, Donostia-SanSebastián, Spain javier.sanchezabuin@osakidetza.net Abstract. A surgical technique currently used in the treatment of Abdominal Aortic Aneurysms (AAA) is the Endovascular Aneurysm Repair (EVAR). This minimally invasive procedure involves inserting a prosthesis in the aortic vessel that excludes the aneurysm from the bloodstream. The stent, once in place acts as a false lumen for the blood current to travel down, and not into the surrounding aneurysm sac. This procedure, therefore, immediately takes the pressure off the aneurysm, which thromboses itself after some time. Nevertheless, in a long term perspective, different complications such as prosthesis displacement or bloodstream leaks into or from the aneurysmatic bulge (endoleaks) could appear causing a pressure elevation and, as a result, increasing the danger of rupture. The purpose of this work is to explore the application of image registration techniques to the visual detection of changes in the thrombus in order to assess the evolution of the aneurysm. Prior to registration, both the lumen and the thrombus are segmented. 1 Introduction Abdominal Aortic Aneurysms (AAA) [1, 2] are a focal dilation in some point of the abdominal section of the aorta. Several treatments exist today; one option is a minimally invasive surgical procedure called Endovascular Aneurysm Repair (EVAR) in which an endovascular prosthesis (endovascular graft) is inserted to exclude the aneurysm from blood circulation [3]. The EVAR (Fig.1) requires a postoperative follow-up to ensure that the stent is stable (absence of leakage, i.e.: blood flow within the aneurysm’s sack). A reduction in the size of the aneurysm ensures that exclusion has been effective [4, 5], while an