title: Comparison of atlas- and magnetic-resonance-imaging-based stereotactic targeting of the subthalamic nucleus in the surgical treatment of Parkinson's disease.
abstract: OBJECTIVE
  To assess the variability of the subthalamic nucleus (STN) size, orientation and target coordinates from direct visualization on high-resolution magnetic resonance (MR) images in patients undergoing surgical intervention for Parkinson's disease.
  
  
  METHODS
  Sixty-six patients with Parkinson's disease were included in this study. The STN was visualized directly on high-resolution MR images, the size and orientation in both coronal and axial planes were recorded, as were the coordinates of the dorsolateral STN target in relation to the anterior-posterior commissural (AC-PC) line. The same STN target was defined in the Schaltenbrand atlas and atlas-based coordinates in proportion to the patient's AC-PC dimension were calculated. MR-imaging-based STN target coordinates were compared with the corresponding atlas-based coordinates.
  
  
  RESULTS
  Marked variation of STN size and orientation was observed. A significant difference was demonstrated on comparing left- and right-sided x and y coordinates. The comparison between MR-imaging-based and atlas-derived target coordinates demonstrated a significant difference in all directions except the left y coordinate.
  
  
  CONCLUSIONS
  This study demonstrates the substantial individual variability of STN size, orientation and target coordinates and a significant difference between target coordinates obtained by direct visual targeting on MR images and those obtained by indirect targeting based on atlases.
authors.affiliation: Institute of Clinical Neurosciences, Frenchay Hospital, Bristol, UK. Nik.Patel@nbt.nhs.uk
authors.forename: Nikunj K
authors.initials: NK
authors.lastname: Patel
authors.forename: Sadaquate
authors.initials: S
authors.lastname: Khan
authors.forename: Steven S
authors.initials: SS
authors.lastname: Gill
mesh_terms: D001931:Brain Mapping / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D010300:Parkinson Disease / Q000473:pathology / Q000601:surgery*; D013238:Stereotaxic Techniques / Q000592:standards; D020531:Subthalamic Nucleus / Q000033:anatomy & histology* / Q000601:surgery*