Integrating structural and diffusion MR information for optic radiation localisation in focal epilepsy patients

Current state of the art neurosurgical systems do not exploit the complementary information provided by structural and diffusion MRI when aligning pre-operative and intra-operative images. We propose a multivariate registration scheme where structural and fractional anisotropy data are combined in a single similarity measure. We formulate the normalised mutual information expression for the multichannel scheme and compute its analytical derivative. The method was validated using both a numerical phantom and clinical data using pre and post-operative images from patients who had undergone surgery for treatment of refractory focal epilepsy and shows correlation between visual field deficit and predicted damage to the optic radiation. This work could be of significant utility in image-guided interventions and facilitate effective surgical treatments.