title: Evaluation of the PI-RADS scoring system for mpMRI of the prostate: a whole-mount step-section analysis.
abstract: OBJECTIVE
  Evaluation of the Prostate Imaging Reporting and Data System (PI-RADS) scoring system for classifying multi-parametric magnetic resonance imaging findings of the prostate using whole-mount step-section slides as reference standard.
  
  
  METHODS
  Prospective inclusion of 50 consecutive patients with biopsy-proven prostate cancer (PCa). All patients received a multi-parametric MRI of the prostate, consisting of T2-weighted, diffusion-weighted, and dynamic contrast-enhanced MRI. After prostatectomy, all prostates were prepared as whole-mount step-section slides. For each patient, six lesions were predefined on whole-mount step-sections according to a distinct scheme and the corresponding regions were identified on MRI. Each lesion then was scored on MRI according to PI-RADS by an experienced blinded uro-radiologist and compared with histopathological findings.
  
  
  RESULTS
  PCa received significant (p < 0.01) higher overall PI-RADS scores (4.10 ± 0.75) compared with benign changes (2.00 ± 0.74). In the peripheral zone, each single modality score showed good diagnostic accuracy for PCa detection (area under the curve [AUC] > 0.90). When combining all single modality scores, an even higher discriminative ability of PCa detection (AUC = 0.97, 95 % CI 0.95-0.99) could be achieved. In contrast, in the transitional zone, dynamic contrast-enhanced MRI (DCE) showed very low diagnostic accuracy (AUC = 0.60). Regarding tumor malignancy, no high-grade PCa (Gleason >7a) was present at PI-RADS scores <4 and no Gleason 6 PCa at a PI-RADS score of 5.
  
  
  CONCLUSIONS
  The PI-RADS scoring system showed good diagnostic accuracy: Only PI-RADS 4 and 5 showed high-grade PCa. However, it seems necessary to revise the PI-RADS scoring system concerning DCE in the transitional zone.
authors: Department of Radiology, Medical University Innsbruck, Anichstraße 35, 6020, Innsbruck, Austria, daniel.junker@uki.at.
authors: Daniel
authors: D
authors: Junker
authors: Michael
authors: M
authors: Quentin
authors: Udo
authors: U
authors: Nagele
authors: Michael
authors: M
authors: Edlinger
authors: Jonathan
authors: J
authors: Richenberg
authors: Georg
authors: G
authors: Schaefer
authors: Michael
authors: M
authors: Ladurner
authors: Werner
authors: W
authors: Jaschke
authors: Wolfgang
authors: W
authors: Horninger
authors: Friedrich
authors: F
authors: Aigner
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012372:ROC Curve