Retrospective Registration for Improved Localization of Cortical Stimulation on MR Images.

Tynan Reid Stevens¹, Ryan CN D'Arcy¹, Steven D. Beyea¹, David B. Clarke²

Localization of cortical stimulation (CS) measurements on MR images is subject to error from brain shift at time of dural opening. We present a method for using digitized CS points and a cortical surface mask extracted from a high-resolution MRI to compute first order corrections for brain shift. CS measurements were recorded for nine brain tumor patients using a neuronavigation system. An iterative-closest-point algorithm was developed to minimize the distance between the CS points and the MR-extracted cortical surface. The mean distance between the CS points and brain surface was reduced from 3.8 +/- 0.5 to 1.6 +/- 0.3 mm.