title: Assessing the microlesion effect of subthalamic deep brain stimulation surgery with FDG PET.
abstract: OBJECTIVE
  The authors investigated whether the insertion of deep brain stimulation electrodes into the subthalamic nucleus can alter regional brain metabolism in the absence of stimulation.
  
  
  METHODS
  Six patients with Parkinson disease (PD) underwent preoperative FDG PET scanning, and again after STN electrode implantation with stimulation turned off.
  
  
  RESULTS
  Compared with baseline values, glucose utilization was reduced in the postoperative off-stimulation scans in the putamen/globus pallidus and in the ventral thalamus (p < 0.01), and there was increased metabolism in the sensorimotor cortex and cerebellum (p < 0.005). The expression of a specific PD-related spatial covariance pattern measured in the FDG PET data did not change after electrode implantation (p = 0.36), nor was there a significant change in clinical motor ratings (p = 0.44). Differences in PD-related spatial covariance pattern expression among the patients after electrode implantation did, however, correlate with the number of microelectrode recording trajectories placed during surgery (r = -0.82, p < 0.05).
  
  
  CONCLUSIONS
  These findings suggest that electrode implantation can impart a microlesion effect on regional brain function. Nonetheless, these local changes did not cross the threshold of network modulation needed to achieve clinical benefit.
authors.affiliation: Departments of Neurology and Medicine, North Shore University Hospital, Manhasset, New York 11030, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Pourfar
authors.forename: Chengke
authors.initials: C
authors.lastname: Tang
authors.forename: Tanya
authors.initials: T
authors.lastname: Lin
authors.forename: Vijay
authors.initials: V
authors.lastname: Dhawan
authors.forename: Michael G
authors.initials: MG
authors.lastname: Kaplitt
authors.forename: David
authors.initials: D
authors.lastname: Eidelberg
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000295:instrumentation*; D004567:Electrodes, Implanted / Q000009:adverse effects; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000601:surgery*; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D020530:Subthalamus / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18