title: 3D neuromelanin-sensitive magnetic resonance imaging with semi-automated volume measurement of the substantia nigra pars compacta for diagnosis of Parkinson's disease.
abstract: BACKGROUND
  Neuromelanin-sensitive MRI has been reported to be used in the diagnosis of Parkinson's disease (PD), which results from loss of dopamine-producing cells in the substantia nigra pars compacta (SNc). In this study, we aimed to apply a 3D turbo field echo (TFE) sequence for neuromelanin-sensitive MRI and to evaluate the diagnostic performance of semi-automated method for measurement of SNc volume in patients with PD.
  
  
  METHODS
  We examined 18 PD patients and 27 healthy volunteers (control subjects). A 3D TFE technique with off-resonance magnetization transfer pulse was used for neuromelanin-sensitive MRI on a 3T scanner. The SNc volume was semi-automatically measured using a region-growing technique at various thresholds (ranging from 1.66 to 2.48), with the signals measured relative to that for the superior cerebellar peduncle. Receiver operating characteristic (ROC) analysis was performed at all thresholds. Intra-rater reproducibility was evaluated by intraclass correlation coefficient (ICC).
  
  
  RESULTS
  The average SNc volume in the PD group was significantly smaller than that in the control group at all the thresholds (P < 0.01, student t test). At higher thresholds (>2.0), the area under the curve of ROC (Az) increased (0.88). In addition, we observed balanced sensitivity and specificity (0.83 and 0.85, respectively). At lower thresholds, sensitivity tended to increase but specificity reduced in comparison with that at higher thresholds. ICC was larger than 0.9 when the threshold was over 1.86.
  
  
  CONCLUSIONS
  Our method can distinguish the PD group from the control group with high sensitivity and specificity, especially for early stage of PD.
authors.affiliation: Department of Radiology, Hokkaido University Graduate School of Medicine, N-15, W-7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan.
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Ogisu
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Kudo
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.forename: Ken
authors.initials: K
authors.lastname: Sakushima
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yabe
authors.forename: Hidenao
authors.initials: H
authors.lastname: Sasaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Terae
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008543:Melanins / Q000378:metabolism*; D057054:Molecular Imaging / Q000379:methods; D009929:Organ Size; D010300:Parkinson Disease / Q000378:metabolism* / Q000473:pathology*; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013378:Substantia Nigra / Q000378:metabolism* / Q000473:pathology*; D014018:Tissue Distribution
chemical_list: D015415:Biomarkers; D008543:Melanins; C014121:neuromelanin