Intensity-based MRI to X-ray mammography registration with an integrated fast biomechanical transformation

Abstract

Determining MRI to X-ray mammography correspondence is a clinically useful task that is challenging for radiologists due to the large deformation that the breast undergoes. In this work we propose an intensity-based registration framework with a new integrated transformation module that uses a biomechanical model of the breast in order to simulate the mammographic compression. The breast model is patient-specific and is extracted from the MRI of the patient. The transformation model has seven degrees of freedom and uses a fast explicit Finite Element (FE) solver that runs on the graphics card, enabling it to be fully integrated into the optimisation scheme. The iteratively updated parameters include both parameters of the biomechanical model simulation, and also rigid transformation parameters of the breast geometry model. The framework was tested on five clinical cases. The mean registration error was 7.6±2.4mm for the CC and 10.2±2.3mm for the MLO view registrations, indicating that this could be a useful clinical tool. © 2012 Springer-Verlag Berlin Heidelberg.