Magnetic resonance (MR) and computed tomography (CT) images provide a detailed 3-D description of patient anatomy. During neurosurgery it is often desirable to establish a correspondence between these pre-operative images and real-time images of the patient (as shown to the right). In so doing, the position of a surgical target (e.g., a tumor), clearly visible in the MR or CT image, can be more easily visualized by the surgeon.

We have developed a system that allows for the real-time overlay of pre-operative MR or CT imagery onto a surgeon's operating microscope view. To accomplish this, our system estimates the transformation between the pre-operative image space and the continually changing surgical space - this estimation must be accurate to within 1 mm.

(Collaborative work with Hai Sun and Keith Paulsen)