Image registration for interventional MRI-guided minimally invasive treatment of prostate cancer

We are investigating automatic image registration methods that can be used for interventional magnetic resonance imaging (iMRI) guided radiofrequency (RF) thermal ablation of prostate cancer. We tested the ability of slice-to-volume registration between iMRI slice images and high-resolution MRI volumes. Images were acquired from a conventional 1.5 T and an interventional 0.2 T MRI system. We evaluated the registration quality by calculating 3D displacement on a voxel-by-voxel basis over a volume of interest between slice-to-volume registration and volume-to-volume registration that was previously shown to be quite accurate. Visual inspections such as color overlay and contour overlap were also used for registration evaluation. More than 300 registration experiments were performed on MR images of volunteers. Results showed that the registration was quite robust and accurate (<2 mm) for the transverse images covering the prostate.