Abstract. Stereotactic techniques are prevalent in neurosurgery. A fundamental assumption of stereotaxis is that the brain is a rigid body. It has been demonstrated, however, that following a craniotomy the brain tissue will shift by 10 mm on average. We are investigating intra-operative ultrasound, using an optical tracking system to record the position and orientation of the ultrasound probe, as a method of measuring and correcting for brain shift. We have determined that the accuracy to which ultrasound image coordinates can be tracked (including the errors involved in calibration) is better than 0.5 mm within the ultrasound image plane, and better than 2 mm perpendicular to the plane. We apply two visualization methods to compare the ultrasound and the pre-operative MRI: the first is real-time overlay of the ultrasound with the co-planar MR slice, and the second is the real-time texture mapping of the ultrasound video into a 3D view with the MRI. Our technique is demonstrated on a...
David G. Gobbi, Roch M. Comeau, Terry M. Peters