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

PURPOSE: 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).

METHODS

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.

RESULTS

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: kE = 1718 voxels; right: kE = 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).

CONCLUSIONS

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.