title: Standardized Reporting of Prostate MRI: Comparison of the Prostate Imaging Reporting and Data System (PI-RADS) Version 1 and Version 2.
abstract: BACKGROUND
  Objective of our study was to determine the agreement between version 1 (v1) and v2 of the Prostate Imaging Reporting and Data System (PI-RADS) for evaluation of multiparametric prostate MRI (mpMRI) and to compare their diagnostic accuracy, their inter-observer agreement and practicability.
  
  
  METHODS
  mpMRI including T2-weighted imaging, diffusion-weighted imaging (DWI) and dynamic contrast-enhanced imaging (DCE) of 54 consecutive patients, who subsequently underwent MRI-guided in-bore biopsy were re-analyzed according to PI-RADS v1 and v2 by two independent readers. Diagnostic accuracy for detection of prostate cancer (PCa) was assessed using ROC-curve analysis. Agreement between PI-RADS versions and observers was calculated and the time needed for scoring was determined.
  
  
  RESULTS
  MRI-guided biopsy revealed PCa in 31 patients. Diagnostic accuracy for detection of PCa was equivalent with both PI-RADS versions for reader 1 with sensitivities and specificities of 84%/91% (AUC = 0.91 95%CI[0.8-1]) for PI-RADS v1 and 100%/74% (AUC = 0.92 95% CI[0.8-1]) for PI-RADS v2. Reader 2 achieved similar diagnostic accuracy with sensitivity and specificity of 74%/91% (AUC = 0.88 95%CI[0.8-1]) for PI-RADS v1 and 81%/91% (AUC = 0.91 95%CI[0.8-1]) for PI-RADS v2. Agreement between scores determined with different PI-RADS versions was good (reader 1: κ = 0.62, reader 2: κ = 0.64). Inter-observer agreement was moderate with PI-RADS v2 (κ = 0.56) and fair with v1 (κ = 0.39). The time required for building the PI-RADS score was significantly lower with PI-RADS v2 compared to v1 (24.7±2.3 s vs. 41.9±2.6 s, p<0.001).
  
  
  CONCLUSIONS
  Agreement between PI-RADS versions was high and both versions revealed high diagnostic accuracy for detection of PCa. Due to better inter-observer agreement for malignant lesions and less time demand, the new PI-RADS version could be more practicable for clinical routine.
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Tewes
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Klinikum der Region Hannover, Hannover, Gehrden, Germany.
authors.forename: Nikolaj
authors.initials: N
authors.lastname: Mokov
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Hartung
authors.affiliation: Clinic for Urology, Klinikum der Region Hannover, Hannover, Gehrden, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Schick
authors.affiliation: Department of Urology and Urologic Oncology, Hannover Medical School, Hannover, Germany.
authors.forename: Inga
authors.initials: I
authors.lastname: Peters
authors.affiliation: Clinic for Urology, Klinikum der Region Hannover, Hannover, Gehrden, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Schedl
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Pertschy
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Wacker
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Klinikum der Region Hannover, Hannover, Gehrden, Germany.
authors.forename: Götz
authors.initials: G
authors.lastname: Voshage
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Hueper