title: Imaging of nigrosome 1 in substantia nigra at 3T using multiecho susceptibility map-weighted imaging (SMWI).
abstract: To enhance the visibility of nigrosome 1 in substantia nigra, which has recently been suggested as an imaging biomarker for Parkinson's disease (PD) at 3T magnetic resonance imaging (MRI).
  
  
  
  The substantia nigra structure was visualized at 3T MRI using multiecho susceptibility map-weighted imaging (SMWI) in 15 healthy volunteers and 6 patients with Parkinson's disease (PD). The visibility of nigrosome 1 was further enhanced by acquiring data in an oblique-coronal imaging plane at a high spatial resolution (0.5 × 0.5 × 1.0 mm3). To compare the visibility, the contrast-to-noise ratios (CNR) of the nigrosome 1 structure relative to the neighboring substantia nigra structure were evaluated in the SMWI and other conventional susceptibility contrast images (magnitude, frequency, quantitative susceptibility map [QSM] and susceptibility-weighted image).
  
  
  
  In healthy volunteers, the CNRs of the nigrosome 1 structure were 1.04 ± 0.38, 0.84 ± 0.32, 1.04 ± 0.40, 0.86 ± 0.41, and 1.45 ± 0.48 for magnitude, frequency, quantitative susceptibility map, susceptibility-weighted image, and SMWI, respectively. Compared to conventional susceptibility contrast images, the SMWI method significantly improved the CNR of nigrosome 1 (P = 0.014 for magnitude, P = 0.030 for QSM, and P < 0.001 for frequency and SWI, respectively). The magnetic susceptibility difference between nigrosome 1 and neighboring substantia nigra structures was 0.037 ± 0.016 ppm (measured in QSM, P < 0.001) in healthy volunteers. In the PD patients, the visibility of the nigrosome 1 structures was reduced.
  
  
  
  The SMWI method enhances the visibility of nigrosome 1 structures at 3T MRI when compared to conventional susceptibility contrast images.
  
  
  
  3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:528-536.
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yoonho
authors.initials: Y
authors.lastname: Nam
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Gho
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Radiology, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Eung Yeop
authors.initials: EY
authors.lastname: Kim
authors.affiliation: Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea.
authors.forename: Jongho
authors.initials: J
authors.lastname: Lee
mesh_terms: D000368:Aged; D015415:Biomarkers; D001931:Brain Mapping; D003287:Contrast Media / Q000737:chemistry; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D013378:Substantia Nigra / Q000000981:diagnostic imaging*
chemical_list: D015415:Biomarkers; D003287:Contrast Media
keywords: Parkinson's disease; iron deposition; magnetic resonance imaging; nigrosome 1; quantitative susceptibility mapping; substantia nigra