title: 1.5T versus 3T MRI for targeting subthalamic nucleus for deep brain stimulation.
abstract: BACKGROUND
  Accurate stereotactic placement of the electrode into the subthalamic nucleus (STN) is imperative to the therapeutic efficacy of deep brain stimulation (DBS). However, it is not always possible to directly visualize the very small STN using 1.5T MR imaging.
  
  
  OBJECTIVE
  To evaluate whether 3T MR imaging can provide better identification of the STN and clinical outcome than 1.5T MR imaging.
  
  
  METHODS
  Thirty-nine patients with advanced Parkinson's disease underwent 1.5T (n = 16) or 3T (n = 23) fast spin echo T2-weighted (FSE-T2WI) MR imaging for targeting the STN. A semi-quantitative 3-point scoring system was proposed to rank the clearness of STN contour: Score "0" if non-visible; Score "1" if visible but with blurred margin; and "2" if visible with clear margin. The unified Parkinson's disease rating scale (UPDRS) was also compared before operation and post-operation.
  
  
  RESULTS
  The STN score was 2 in all the patients of the 3T group, whereas it was relatively blurred (mean score, 1.19) in the 1.5T group (P < 0.001). The number of microelectrode trajectories (1.2 versus 1.5; P < 0.05) was lower in the 3T group; consequently, the operative time was also less (P < 0.05) as compared with that in the 1.5T group. The outcome of UPDRS motor examination showed no significant difference in two groups.
  
  
  CONCLUSIONS
  3T MR imaging is a reliable and more accurate method for direct targeting of the STN for DBS surgery. However, the technique of high-sequence MR imaging may not influence the clinical outcome significantly.
authors.affiliation: Graduate Institute of Clinical Medical Science, China Medical University , Taichung , Taiwan.
authors.forename: Cheng-Hsin
authors.initials: CH
authors.lastname: Cheng
authors.forename: Hsing-Ming
authors.initials: HM
authors.lastname: Huang
authors.forename: Hung-Lin
authors.initials: HL
authors.lastname: Lin
authors.forename: Shang-Ming
authors.initials: SM
authors.lastname: Chiou
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000628:therapy*; D013238:Stereotaxic Techniques; D020531:Subthalamic Nucleus / Q000601:surgery*; D016896:Treatment Outcome
keywords: Parkinson's disease; deep brain stimulation; functional neurosurgery; magnetic resonance image; subthalamic nucleus