title: Comparison of 2-dimensional magnetic resonance imaging and 3-planar reconstruction methods for targeting the subthalamic nucleus in Parkinson disease.
abstract: OBJECTIVE
  The study aims to compare 2-dimensional (2D) and 3-planar (3P) reconstruction magnetic resonance imaging (MRI) methods of targeting the optimal region of the subthalamic nucleus (STN) for chronic stimulation in patients with Parkinson disease.
  
  
  METHODS
  We studied 14 patients with Parkinson disease treated with bilateral STN deep brain stimulation (DBS) (28 STN targets). Electrode implantation was based on direct and indirect targeting based upon the position of the anterior and posterior commissures using 2D MRI, with selection of the final target based on microelectrode recording. Optimal settings, including the contacts used, were determined during the clinical follow-up. The position of the best contact was defined with postoperative MRI. Optimal contact position was compared to targets calculated by the direct method from the preoperative 2D MRI and 3P reconstruction. Optimal contact position was also compared to the indirect targets calculated from the preoperative 2D MRI and 3P reconstruction. The distance between the targets and the position of the best contact were calculated.
  
  
  RESULTS
  The mean improvement in OFF-period Unified Parkinson Disease Rating Scale III subscores with STN DBS was 52%. The mean distance between the optimal contact position and the direct target was 4.66 mm (SD = 1.33) using the 2D MRI and 3.49 mm (SD = 1.29) using the 3P reconstruction (t test, P < .001). The mean distance between the optimal contact and the indirect target was 3.42 mm (SD = 1.34) using the 2D MRI and 2.61 mm (SD = 0.97; t test, P = .001) using the 3P reconstruction. The variance of the direct target was less using the 3P reconstruction than using the 2D MRI (F test, P = .002), indicating greater precision. Similarly, the variance of the indirect target using the 3P reconstruction was less than using the 2D MRI (F test, P = .012).
  
  
  CONCLUSIONS
  Indirect and direct targets chosen using 3P reconstruction more closely approximate the position of the clinically optimal contact than targets chosen using 2D MRI.
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of Toronto and University Health Network, Toronto, Ontario, M5T 2S8, Canada.
authors.forename: Yuri M
authors.initials: YM
authors.lastname: Andrade-Souza
authors.forename: Jason M
authors.initials: JM
authors.lastname: Schwalb
authors.forename: Clement
authors.initials: C
authors.lastname: Hamani
authors.forename: Tasnuva
authors.initials: T
authors.lastname: Hoque
authors.forename: Jean
authors.initials: J
authors.lastname: Saint-Cyr
authors.forename: Andres M
authors.initials: AM
authors.lastname: Lozano
mesh_terms: D046690:Deep Brain Stimulation / Q000379:methods*; D004567:Electrodes, Implanted; D007839:Functional Laterality; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D010300:Parkinson Disease / Q000473:pathology / Q000628:therapy*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D020531:Subthalamic Nucleus / Q000473:pathology*