title: Improved subthalamic nucleus depiction with quantitative susceptibility mapping.
abstract: OBJECTIVE
  To assess quantitative susceptibility mapping (QSM) in the depiction of the subthalamic nucleus (STN) by using 3-T magnetic resonance (MR) imaging.
  
  
  METHODS
  This study was HIPAA compliant and institutional review board approved. Ten healthy subjects (five men, five women; mean age, 24 years ± 3 [standard deviation]; age range, 21-33 years) and eight patients with Parkinson disease (five men, three women; mean age, 57 years ± 14; age range, 25-69 years) who were referred by neurologists for preoperative navigation MR imaging prior to deep brain stimulator placement were included in this study. T2-weighted (T2w), T2*-weighted (T2*w), R2* mapping (R2*), phase, susceptibility-weighted (SW), and QSM images were reconstructed for STN depiction. Qualitative visualization scores of STN and internal globus pallidus (GPi) were recorded by two neuroradiologists on all images. Contrast-to-noise ratios (CNRs) of the STN and GPi were also measured. Measurement differences were assessed by using the Wilcoxon rank sum test and the signed rank test.
  
  
  RESULTS
  Qualitative scores were significantly higher on QSM images than on T2w, T2*w, R2*, phase, or SW images (P < .05) for STN and GPi visualization. Median CNR was 6.4 and 10.7 times higher on QSM images than on T2w images for differentiation of STN from the zona incerta and substantia nigra, respectively, and was 22.7 and 9.1 times higher on QSM images than on T2w images for differentiation of GPi from the internal capsule and external globus pallidus, respectively. CNR differences between QSM images and all other images were significant (P < .01).
  
  
  CONCLUSIONS
  QSM at 3-T MR imaging performs significantly better than current standard-of-care sequences in the depiction of the STN.
authors.affiliation: Departments of Radiology and Neurological Surgery, Weill Cornell Medical College, 525 E 68th St, Box 141, New York, NY, 10021.
authors.forename: Tian
authors.initials: T
authors.lastname: Liu
authors.forename: Sarah
authors.initials: S
authors.lastname: Eskreis-Winkler
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Schweitzer
authors.forename: Weiwei
authors.initials: W
authors.lastname: Chen
authors.forename: Michael G
authors.initials: MG
authors.lastname: Kaplitt
authors.forename: A John
authors.initials: AJ
authors.lastname: Tsiouris
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D046690:Deep Brain Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000473:pathology* / Q000534:rehabilitation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020531:Subthalamic Nucleus / Q000473:pathology*; D055815:Young Adult