title: Correlation of diffusion tensor tractography and intraoperative macrostimulation during deep brain stimulation for Parkinson disease.
abstract: OBJECTIVE
  The purpose of this study was to investigate whether diffusion tensor imaging (DTI) of the corticospinal tract (CST) is a reliable surrogate for intraoperative macrostimulation through the deep brain stimulation (DBS) leads. The authors hypothesized that the distance on MRI from the DBS lead to the CST as determined by DTI would correlate with intraoperative motor thresholds from macrostimulations through the same DBS lead.
  
  
  METHODS
  The authors retrospectively reviewed pre- and postoperative MRI studies and intraoperative macrostimulation recordings in 17 patients with Parkinson disease (PD) treated by DBS stimulation. Preoperative DTI tractography of the CST was coregistered with postoperative MRI studies showing the position of the DBS leads. The shortest distance and the angle from each contact of each DBS lead to the CST was automatically calculated using software-based analysis. The distance measurements calculated for each contact were evaluated with respect to the intraoperative voltage thresholds that elicited a motor response at each contact.
  
  
  RESULTS
  There was a nonsignificant trend for voltage thresholds to increase when the distances between the DBS leads and the CST increased. There was a significant correlation between the angle and the voltage, but the correlation was weak (coefficient of correlation [R] = 0.36).
  
  
  CONCLUSIONS
  Caution needs to be exercised when using DTI tractography information to guide DBS lead placement in patients with PD. Further studies are needed to compare DTI tractography measurements with other approaches such as microelectrode recordings and conventional intraoperative MRI-guided placement of DBS leads.
authors: Departments of Radiology, Neuroradiology Division;
authors: Nicholas
authors: N
authors: Said
authors: W Jeff
authors: WJ
authors: Elias
authors: Prashant
authors: P
authors: Raghavan
authors: Alan
authors: A
authors: Cupino
authors: Nicholas
authors: N
authors: Tustison
authors: Robert
authors: R
authors: Frysinger
authors: James
authors: J
authors: Patrie
authors: Wenjun
authors: W
authors: Xin
authors: Max
authors: M
authors: Wintermark
mesh_terms: D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000601:surgery*; D011712:Pyramidal Tracts; D012189:Retrospective Studies
keywords: CST = corticospinal tract; DBS = deep brain stimulation; DTI = diffusion tensor imaging; GEE = generalized estimating equation; GPi = globus pallidus internus; MPRAGE = magnetization-prepared rapid acquisition gradient echo; NEX = number of excitations; PD = Parkinson disease; STN = subthalamic nucleus; Vim = ventral intermediate nucleus; deep brain stimulation; diffusion tensor tractography; functional neurosurgery