The Anatomical and Electrophysiological Subthalamic Nucleus Visualized by 3-T Magnetic Resonance Imaging

BACKGROUND: Accurate localization of the subthalamic nucleus (STN) is critical to the success of deep brain stimulation surgery for Parkinson disease. Recent developments in high-field-strength magnetic resonance imaging (MRI) have made it possible to visualize the STN in greater detail. However, the relationship of the MR-visualized STN to the anatomic, electrophysiological, or atlas-predicted STN remains controversial. OBJECTIVE: To evaluate the size of the STN visualized on 3-T MRI compared with anatomic measurements in cadaver studies and to compare the predictions of 3-T MRI and those of the Schaltenbrand-Wahren (SW) atlas for intraoperative STN microelectrode recordings. METHODS: We evaluated the STN by 3-T MRI and intraoperative microelectrode recordings in 20 Parkinson disease patients undergoing deep brain stimulation surgery. We compared our findings with anatomic cadaver studies and with the individually scaled SW atlas-based predictions for each patient. RESULTS: The dimensions of the 3-T MR-visualized STN were very similar to those of the largest anatomic study (MRI length, width, and height: 9.8 +/- 1.6, 11.5 +/- 1.6, and 3.7 +/- 0.7 mm, respectively; n = 40; cadaver length, width, and height: 9.3 +/- 0.7, 10.6 +/- 0.9, and 3.1 +/- 0.5 mm, respectively; n = 100). The amount of STN traversed during intraoperative microelectrode recordings was better correlated to the 3-T MR-visualized STN than the SW atlas-predicted STN (R = 0.38 vs R = 20.17). CONCLUSION: The STN as visualized on 3-T MRI corresponds well with cadaveric anatomic studies and intraoperative electrophysiology. STN visualization with 3-T MRI may be an improvement over SW atlas-based localization for STN deep brain stimulation surgery in Parkinson disease.