[¹⁸F]FDG-PET reveals early postoperative cortical dysfunction after subthalamic nucleus deep brain stimulation in Parkinson's disease.

Abstract

Motor improvement and neuropsychiatric symptoms may immediately follow implantation of subthalamic nucleus deep brain stimulation (STN-DBS) electrodes in Parkinson's disease (PD). We investigated the impact of electrode implantation prior to stimulation on transient dysfunction using cerebral [¹⁸F]fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET). Additionally, we sought to identify clinical and imaging variables associated with neuropsychiatric side effects (SE). This retrospective analysis included thirteen patients with advanced PD, receiving [¹⁸F]FDG-PET scans preoperatively and within three weeks (median 6 days) after STN-DBS surgery. We analyzed changes of regional metabolism in a voxel-wise manner and with volumes-of-interests. Moreover, we evaluated the extent and magnitude of metabolic decrease alongside the electrode trajectories. Neuropsychiatric SE were defined as novel, surgery-related neuropsychiatric symptoms listed in clinical records. PET analyses revealed hypometabolism along the electrodes (mean magnitude up to -35.9 ± 18.0% and mean extent of 19.9 ± 10.2 ml per hemisphere) largely located in the frontal lobe (left: k_E = 1718 voxels; right: k_E = 1550 voxels, p < 0.05, false discovery rate corrected). Patients with neuropsychiatric SE were older (61 vs. 55 years; p = 0.043) and had lower normalized [¹⁸F]FDG uptake in the middle frontal gyrus (MFG) preoperatively (1.01 vs. 1.06; p = 0.030). Preoperative metabolism in the MFG and age were indicative of the occurrence of neuropsychiatric SE (area under the Receiver Operating Characteristic curve = 0.90). Reversible neuronal dysfunction after STN-DBS surgery can be detected by [¹⁸F]FDG-PET along the electrode trajectory. Preoperative MFG metabolism and age were associated with postoperative neuropsychiatric SE supporting the use of PET to improve patient selection and postoperative care concepts.