Variability in position of the subthalamic nucleus targeted by magnetic resonance imaging and microelectrode recordings as compared to atlas co-ordinates

Background: Traditional methods for localisation of target nuclei for deep brain stimulation (DBS) have used brain atlas co-ordinates for initial targeting. It is now possible to visualise the subthalamic nucleus (STN) on magnetic resonance imaging (MRI) and determine the individual variability of its position. Methods: The present study was performed in patients undergoing STN DBS for Parkinson's disease. The STN was directly targeted from axially obtained MRI and verified with microelectrode recordings. Postoperatively, the most effective contact was identified for each patient, and its position was calculated. Results: Fifty electrodes were inserted in 25 patients. The target position varied considerably in relation to the mid-commissural point. The mean effective contact position lies just dorsal to the location of the STN in a standard brain atlas. Conclusion: The STN varies in position, and can be accurately targeted from MRI alone. Copyright (C) 2003 S. Karger AG, Basel.