Brain shift analysis for deep brain stimulation surgery using non-rigid registration

Deep brain stimulation (DBS) surgery is a treatment for patients suffering from Parkinson's disease and other movement disorders. The success of the procedure depends on the implantation accuracy of the DBS electrode array. Surgical planning and navigation are done based on the pre-operative patient scans, assuming that brain tissues do not move from the time of the pre-operative image acquisition to the time of the surgery. We performed brain shift analysis on nine patients that underwent DBS surgery using a 3D non-rigid registration algorithm. The registration algorithm automatically aligns the pre-operative and the post-operative 3D MRI scans and provides the shift vectors over the entire brain. The images were first aligned rigidly and then non-rigidly registered with an algorithm based on thin plate splines and maximization of the normalized mutual information. Brain shift of up to 8 mm was recorded in the nine subjects, which is significant given that the size of the targets in the DBS surgery is a few millimeters.