title: Correlation between neuromelanin-sensitive MR imaging and (123)I-FP-CIT SPECT in patients with parkinsonism.
abstract: BACKGROUND
  Neuromelanin-sensitive MR imaging (MRI) can visualize neuromelanin-containing neurons in the substantia nigra pars compacta (SNc), and its utility has been reported in the evaluation of parkinsonism. Conversely, dopamine transporter imaging by (123)I-N-v-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl)nortropane (FP-CIT) SPECT (DaTSCAN) is now an established method for evaluating parkinsonism, detecting presynaptic dopamine neuronal dysfunction. Both methods can assist differentiating neurodegenerative and other forms of parkinsonism. However, to our knowledge, there have been no studies concerning a correlation between the two methods. The aim of this study was to assess the utility of neuromelanin-sensitive MRI for diagnosing parkinsonism by examining a correlation with DaTSCAN.
  
  
  METHODS
  Twenty-three patients with parkinsonism who underwent both neuromelanin-sensitive MRI and DaTSCAN were included. We measured the neuromelanin-positive SNc region volume by manually contouring the high signal intensity region of the SNc on neuromelanin-sensitive MRI and measured the specific binding ratio (SBR) on DaTSCAN. The asymmetry index of neuromelanin-positive SNc volume and the asymmetry index of SBR were also calculated.
  
  
  RESULTS
  The volume of the neuromelanin-positive SNc region showed significant correlation with specific binding ratio (SBR) (right P < .001, ρ = 0.78, left P < .001, ρ = 0.86). The asymmetry index of neuromelanin-positive SNc volume also showed significant correlations with the asymmetry index of SBR (P < .001, ρ = 0.73).
  
  
  CONCLUSIONS
  Decrease of the high signal intensity region of the SNc on neuromelanin-sensitive MRI would indicate damage to the nigrostriatal dopaminergic function as well as loss of dopaminergic neurons. We conclude that neuromelanin-sensitive MRI is a useful diagnostic biomarker for parkinsonism.
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, 683-8504, Japan. keita98_1_7@hotmail.co.jp.
authors.forename: Keita
authors.initials: K
authors.lastname: Kuya
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, 683-8504, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shinohara
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, 683-8504, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Miyoshi
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, 683-8504, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Fujii
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, 683-8504, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tanabe
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, 683-8504, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008543:Melanins / Q000378:metabolism*; D008875:Middle Aged; D020734:Parkinsonian Disorders / Q000000981:diagnostic imaging* / Q000378:metabolism; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes
chemical_list: D015415:Biomarkers; D008543:Melanins; D014326:Tropanes; C014121:neuromelanin; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane
keywords: 123I-FP-CIT SPECT; Neuromelanin-sensitive MRI; Parkinsonism; Specific binding ratio