Proceedings Article | 13 March 2009
Proc. SPIE. 7261, Medical Imaging 2009: Visualization, Image-Guided Procedures, and Modeling
KEYWORDS: Image segmentation, Visualization, Angiography, Image registration, Surgery, Computed tomography, Rigid registration, Medical imaging, Control systems, Abdomen
Quantification of abdominal aortic deformation is an important requirement for the evaluation of endovascular stenting
procedures and the further refinement of stent graft design. During endovascular aortic repair (EVAR) treatment, the aortic
shape is subject to severe deformation that is imposed by medical instruments such as guide wires, catheters, and, the
stent graft. This deformation can affect the flow characteristics and morphology of the aorta which have been shown to
be elicitors for stent graft failures and be reason for reappearance of aneurysms. We present a method for quantifying the
deformation of an aneurysmatic aorta imposed by an inserted stent graft device. The outline of the procedure includes
initial rigid alignment of the two abdominal scans, segmentation of abdominal vessel trees, and automatic reduction of
their centerline structures to one specified region of interest around the aorta. This is accomplished by preprocessing and
remodeling of the pre- and postoperative aortic shapes before performing a non-rigid registration. We further narrow the
resulting displacement fields to only include local non-rigid deformation and therefore, eliminate all remaining global rigid
transformations. Finally, deformations for specified locations can be calculated from the resulting displacement fields.
In order to evaluate our method, experiments for the extraction of aortic deformation fields are conducted on 15 patient
datasets from endovascular aortic repair (EVAR) treatment. A visual assessment of the registration results and evaluation
of the usage of deformation quantification were performed by two vascular surgeons and one interventional radiologist
who are all experts in EVAR procedures.
