System and method for 3-D/3-D registration between non-contrast-enhanced CBCT and contrast-enhanced CT for abdominal aortic aneurysm stenting.

In this paper, we present an image guidance system for abdominal aortic aneurysm stenting, which brings pre-operative 3-D computed tomography (CT) into the operating room by registering it against intra-operative non-contrast-enhanced cone-beam CT (CBCT). Registration between CT and CBCT volumes is a challenging task due to two factors: the relatively low signal-to-noise ratio of the abdominal aorta in CBCT without contrast enhancement, and the drastically different field of view between the two image modalities. The proposed automatic registration method handles the first issue through a fast quasi-global search utilizing surrogate 2-D images, and solves the second problem by relying on neighboring dominant structures of the abdominal aorta (i.e. the spine) for initial coarse alignment, and using a confined and image-processed volume of interest around the abdominal aorta for fine registration. The proposed method is validated offline using 17 clinical datasets, and achieves 1.48 mm target registration error and 100% success rate in 2.83 s. The prototype system has been installed in hospitals for clinical trial and applied in around 30 clinical cases, with 100% success rate reported qualitatively.