Robust 2-D/3-D registration of CT volumes with contrast-enhanced X-ray sequences in electrophysiology based on a weighted similarity measure and sequential subspace optimization

2-D X-ray image navigation during an electrophysiology ablation procedure can be enhanced via the overlay of images derived from pre-operative 3-D data, to provide anatomical details that otherwise are not visible under X-ray. However, accurate registration of 3-D data and 2-D X-ray during electrophysiology ablation is a challenging problem, due to the relatively low image quality and the fact that the contrast medium typically fills only a small part of the left atrium in X-ray images. In this paper, we propose a robust 2-D/3-D registration method tailored for electrophysiology ablation procedures. In particular, a weighted similarity measure is utilized to handle the partial data problem, and a sequential subspace optimization is proposed to take advantage of the available bi-plane X-ray images, for a robust and efficient registration. Since the contrast medium washes out quickly and thus visible in only a small number of frames in the X-ray sequence, we furthermore streamline the workflow by automatically detecting the frame that is optimal for registration purpose. Experimental results on seven clinical data sets demonstrate the effectiveness of the proposed method.