Segmented MRI of the head used to construct a patient specific brain mesh. (a) Tumor segmented in a pre-operative image. (b) Another pre-operative slice of the brain. (c) Brain segmented from image (b). (d) Contour of the brain. Pre-operative images are used to construct computational models of the brain and tumor while the intra-operative images are used to measure the displacements of the anatomical landmarks.