title: Standardized threshold approach using three-dimensional proton magnetic resonance spectroscopic imaging in prostate cancer localization of the entire prostate.
abstract: OBJECTIVE
  We sought to determine the localization accuracy using 3-dimensional (3D) proton magnetic resonance spectroscopic imaging (MRSI) of the entire prostate with a standardized thresholds approach in prostate cancer patients.
  
  
  METHODS
  In a prospective study, 32 consecutive patients were examined. Mean age and prostate specific antigen level were 61 years and 7.8 ng/mL, respectively. Median biopsy Gleason score was 6. T2-weighted MRI and 3D MRSI of the entire prostate were performed. Three readers recorded the location of suspicious peripheral zone and central gland cancer nodules on a standardized division of the prostate (14 regions of interest [ROI]) using a standardized thresholds approach. The degree of diagnostic confidence for each ROI was recorded on a 5-point scale. Reconstructed whole-mount section histopathology was the standard of reference. The sensitivity, specificity, positive, and negative predictive value, overall accuracy and interobserver agreement were calculated. Areas under the ROI-based receiver operating characteristic curve (AUC) and diagnostic performance parameters were determined.
  
  
  RESULTS
  The standardized thresholds approach had an accuracy of 81% and an AUC of 0.85-0.86 for differentiation between benign and malignant ROIs in the peripheral zone and an accuracy of 87% and an AUC of 0.86-0.91 for this differentiation in the central gland, respectively. Specificities of 81% to 88% were achieved with accompanying sensitivities of 75% to 92% for both peripheral zone and central gland, respectively. Moderate to near-perfect interobserver agreement was demonstrated (kappa=0.42-0.91).
  
  
  CONCLUSIONS
  Our data indicate that a standardized zone-specific threshold approach in MRSI of the prostate is able to prospectively differentiate between benign and malignant tissues in the peripheral zone and the central gland with good accuracy and interobserver agreement.
authors.affiliation: Department of Radiology, Radboud University Nijmegen Medical Center, The Netherlands. J.Futterer@rad.umcn.nl
authors.forename: Jurgen J
authors.initials: JJ
authors.lastname: Fütterer
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Scheenen
authors.forename: Stijn W T P J
authors.initials: SW
authors.lastname: Heijmink
authors.forename: Henkjan J
authors.initials: HJ
authors.lastname: Huisman
authors.forename: Christina A
authors.initials: CA
authors.lastname: Hulsbergen-Van de Kaa
authors.forename: J Alfred
authors.initials: JA
authors.lastname: Witjes
authors.forename: Arend
authors.initials: A
authors.lastname: Heerschap
authors.forename: Jelle O
authors.initials: JO
authors.lastname: Barentsz
mesh_terms: D000368:Aged; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000473:pathology*; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D011522:Protons