Brain shift analysis for deep brain stimulation surgery

Deep brain stimulation (DBS) surgery can significantly improve the quality of life for patients suffering from movement disorders, but the outcome of the surgery greatly depends on the implantation accuracy of the deep brain stimulator. A few millimeter shift in the mid-brain region can influence the results because the pre-operative planning is based on the assumption that anatomical structures do not move between the pre-operative image scan time and the time of the surgery. We studied 15 cases of DBS surgery for possible brain shift between the pre-operative and the post-operative 3D MRI scans. Brain shift of up to 3.8mm was measured after rigidly aligning the pre-operative images with the post-operative images. The rigid registration algorithm has sub-voxel accuracy (registration error of less than 1 mm), and it automatically recovers any rotation around the three axes along with significant translations in the three directions. The brain shift measurements were compared to relevant intra and post operative parameters.