P.116 Anatomical fiducials used to quantify localization and registration accuracy in deep brain stimulation

Background: Studies of deep brain stimulation (DBS) require accurate electrode localization and image registration. We used anatomical fiducials to investigate registration errors in patients who underwent subthalamic nucleus (STN) DBS for Parkinson’s disease (PD). Methods: conducted a retrospective analysis bilateral STN PD. Pre post operative MRI scans were non-linearly normalized standard template (MNI152NLin2009bAsym). Four raters localized electrodes (Lead-DBS), the anterior commissure (AC) posterior (PC). Errors between rater localizations calculated (fiducial error; FLE). transformed AC PC coordinates from patient space calculate fiducial error (FRE)Results: Ninety-nine analyzed, with median FLE 0.76mm, 0.74mm, 0.71mm 0.66mm right electrode, left respectively (no significant difference, Wilcoxon sign rank). The FRE was 1.59mm 1.21mm PC, significantly higher than at those (Wilcoxon rank, p<0.001). Conclusions: Raters can accurately localize electrodes, clinical images sub-millimetric accuracy. Higher FREs suggested may contribute more uncertainty common space.