A fast and robust technique for 3D-2D registration of CT to single plane X-ray fluoroscopy

The application of 3D¿2D image registration can be enormously helpful for different clinical purposes, such as image-guided surgery and the kinematic analysis of bones in knee and ankle joints. A limitation of this approach is the need to recalculate the voxel values in the 3D volume for every iteration of the registration procedure prior to generating a digitally reconstructed radiograph. In this paper we propose a new multi-phase 3D¿2D image registration algorithm which uses partial 3D volumes to estimate out-of-plane rotations. In our proposed algorithm, only one full 3D update is used to generate a 2D projection during the registration procedure. Experimental results show that our proposed method can provide a registration accuracy similar to the commonly used approach which employs 3D updates at every iteration. As a result of reducing the number of 3D updates, the proposed approach reduces the time required to carry out the registration by a factor of 10¿20 without any accompanying loss of registration accuracy.