Deformable image registration of follow-up breast magnetic resonance images

A novel method for the deformable image registration of follow-up breast magnetic resonance (MR) images is proposed, aimed at an automatic synchronization of temporal images. To compensate potentially large breast deformations and differences among device coordinates, an initial linear alignment of each individual breast, a combination of both transformations using thin-plate splines, as well as a subsequent linear-elastic registration are performed in sequence. Complementary to algorithmic details, an overview of modality-specific factors influencing follow-up registration accuracy is given. The proposed method was evaluated on 20 clinical datasets annotated with landmarks by an expert radiologist. Despite large variations among the MR images, accuracy of the method was sufficient to allow spatial synchronization, with remaining target registration errors of <32%. Concluding, potential enhancements to further increase robustness and accuracy are discussed.