Registration of Preoperative CTA and Intraoperative Fluoroscopic Images for Assisting Aortic Stent Grafting

Abstract

We investigated a registration method between preoperative 3D-CTA and intraoperative fluoroscopic images during intervention. Our final goal is assisting endovascular stent grafting for aortic aneurysm. In our method, DRR (Digitally Reconstructed Radiograph) are generated by voxel projection of 3D-CTA after extracting an aorta region. By increasing/decreasing CT value in the aorta region of CTA, DRR with/without contrast media injection are obtained. Subsequently we calculate matching measures between DRR and fluoroscopic images iteratively by changing imaging parameters. The most similar DRR to fluoroscopic image is selected. We investigated characteristics of several matching measures using simulated fluoroscopic images. From simulation results, we use M-estimator of residual in our method. From an application example to clinical data, registration was successfully applied by M-estimator of residual.

Registration-by-regression of coronary CTA and X-ray angiography

“…are caused by the inherent dissimilarity between CTA and X-ray images, while others are related to the imaged object, when for example interventional instruments are present. As inherent differences, we can usually find overlaid structures and different contrast acquisition processes described in the literature (Imamura et al 2002), or differences of CTA and X-ray fields of view (Aksoy et al 2013). In our case, the DRRs were rendered from a 3D CTA-derived coronary model.…”