title: 1.5-T multiparametric MRI using PI-RADS: a region by region analysis to localize the index-tumor of prostate cancer in patients undergoing prostatectomy.
abstract: BACKGROUND
  The use of multiparametric magnetic resonance imaging (mpMRI) to detect and localize prostate cancer has increased in recent years. In 2010, the European Society of Urogenital Radiology (ESUR) published guidelines for mpMRI and introduced the Prostate Imaging Reporting and Data System (PI-RADS) for scoring the different parameters.
  
  
  OBJECTIVE
  To evaluate the reliability and diagnostic performance of endorectal 1.5-T mpMRI using the PI-RADS to localize the index tumor of prostate cancer in patients undergoing prostatectomy.
  
  
  METHODS
  This institutional review board IRB-approved, retrospective study included 63 patients (mean age, 60.7 years, median PSA, 8.0). Three observers read mpMRI parameters (T2W, DWI, and DCE) using the PI-RADS, which were compared with the results from whole-mount histopathology that analyzed 27 regions of interest. Inter-observer agreement was calculated as well as sensitivity, specificity, positive predictive value (PPV), and negative predicted value (NPV) by dichotomizing the PI-RADS criteria scores ≥3. A receiver-operating curve (ROC) analysis was performed for the different MR parameters and overall score.
  
  
  RESULTS
  Inter-observer agreement on the overall score was 0.41. The overall score in the peripheral zone achieved sensitivities of 0.41, 0.60, and 0.55 with an NPV of 0.80, 0.84, and 0.83, and in the transitional zone, sensitivities of 0.26, 0.15, and 0.19 with an NPV of 0.92, 0.91, and 0.92 for Observers 1, 2, and 3, respectively. The ROC analysis showed a significantly increased area under the curve (AUC) for the overall score when compared to T2W alone for two of the three observers.
  
  
  CONCLUSIONS
  1.5 T mpMRI using the PI-RADS to localize the index tumor achieved moderate reliability and diagnostic performance.
authors.affiliation: Department of Radiology, Haukeland University Hospital, Bergen Norway Department of Clinical Medicine, University of Bergen, Norway lars.reisaeter@helse-bergen.no.
authors.forename: Lars A
authors.initials: LA
authors.lastname: Reisæter
authors.affiliation: Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Jurgen J
authors.initials: JJ
authors.lastname: Fütterer
authors.affiliation: Department of Clinical Medicine, University of Bergen, Norway Department of Pathology, Haukeland University Hospital, Bergen Norway.
authors.forename: Ole J
authors.initials: OJ
authors.lastname: Halvorsen
authors.affiliation: Department of Urology, Haukeland University Hospital, Bergen Norway.
authors.forename: Yngve
authors.initials: Y
authors.lastname: Nygård
authors.affiliation: Department of Radiology, Haukeland University Hospital, Bergen Norway Department of Clinical Medicine, University of Bergen, Norway.
authors.forename: Martin
authors.initials: M
authors.lastname: Biermann
authors.affiliation: Department of Clinical Engineering, Haukeland University Hospital, Bergen Norway.
authors.forename: Erling
authors.initials: E
authors.lastname: Andersen
authors.affiliation: Department of Pathology, Haukeland University Hospital, Bergen Norway.
authors.forename: Karsten
authors.initials: K
authors.lastname: Gravdal
authors.affiliation: Department of Clinical Medicine, University of Bergen, Norway Department of Urology, Haukeland University Hospital, Bergen Norway.
authors.forename: Svein
authors.initials: S
authors.lastname: Haukaas
authors.affiliation: Department of Radiology, Haukeland University Hospital, Bergen Norway.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Monssen
authors.affiliation: Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Henkjan J
authors.initials: HJ
authors.lastname: Huisman
authors.affiliation: Department of Clinical Medicine, University of Bergen, Norway.
authors.forename: Lars A
authors.initials: LA
authors.lastname: Akslen
authors.affiliation: Department of Clinical Medicine, University of Bergen, Norway Department of Urology, Haukeland University Hospital, Bergen Norway.
authors.forename: Christian
authors.initials: C
authors.lastname: Beisland
authors.affiliation: Department of Radiology, Haukeland University Hospital, Bergen Norway Department of Clinical Medicine, University of Bergen, Norway.
authors.forename: Jarle
authors.initials: J
authors.lastname: Rørvik
mesh_terms: D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology / Q000601:surgery; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D012372:ROC Curve; D011873:Radiology Information Systems; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: MR diffusion; Urinary; magnetic resonance imaging (MRI); observer performance; prostate