title: Differentiation of prostatitis and prostate cancer using the Prostate Imaging-Reporting and Data System (PI-RADS).
abstract: OBJECTIVE
  To determine if prostate cancer (PCa) and prostatitis can be differentiated by using PI-RADS.
  
  
  METHODS
  3T MR images of 68 patients with 85 cancer suspicious lesions were analyzed. The findings were correlated with histopathology. T2w imaging (T2WI), diffusion weighted imaging (DWI), dynamic contrast enhancement (DCE), and MR-Spectroscopy (MRS) were acquired. Every lesion was given a single PI-RADS score for each parameter, as well as a sum score and a PI-RADS v2 score. Furthermore, T2-morphology, ADC-value, perfusion type, citrate/choline-level, and localization were evaluated.
  
  
  RESULTS
  44 of 85 lesions showed PCa (51.8%), 21 chronic prostatitis (24.7%), and 20 other benign tissue such as hyperplasia or fibromuscular tissue (23.5%). The single PI-RADS score for T2WI, DWI, DCE, as well as the aggregated score including and not including MRS, and the PI-RADS v2-score were all significantly higher for PCa than for prostatitis or other tissue (p<0.001). The single PI-RADS score for MRS and the PI-RADS sum score including MRS were significantly higher for prostatitis than for other tissue (p=0.029 and p=0.020), whereas the other parameters were not different. Prostatitis usually presented borderline pathological PI-RADS scores, showed restricted diffusion with ADC≥900mm(2)/s in 100% of cases, was more often indistinctly hypointense on T2WI (66.7%), and localized in the transitional zone (57.1%). An ADC≥900mm(2)/s achieved the highest predictive value for prostatitis (AUC=0.859).
  
  
  CONCLUSIONS
  Prostatitis can be differentiated from PCa using PI-RADS, since all available parameters are more distinct in cases of cancer. However, there is significant overlap between prostatitis and other benign findings, thus PI-RADS is only suitable to a limited extent for the primary assessment of prostatitis. Restricted diffusion with ADC≥900mm(2)/s is believed to be a good indicator for prostatitis. MRS can help to distinguish between prostatitis and other tissue.
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: michael.meier@ukb.uni-bonn.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Meier-Schroers
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: guido.kukuk@ukb.uni-bonn.de.
authors.forename: Guido
authors.initials: G
authors.lastname: Kukuk
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: karsten.wolter@ukb.uni-bonn.de.
authors.forename: Karsten
authors.initials: K
authors.lastname: Wolter
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: georges.decker@ukb.uni-bonn.de.
authors.forename: Georges
authors.initials: G
authors.lastname: Decker
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: stefan.fischer@ukb.uni-bonn.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Fischer
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: christian.marx@ukb.uni-bonn.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Marx
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: frank.traeber@ukb.uni-bonn.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Traeber
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: sprinkart@uni-bonn.de.
authors.forename: Alois Martin
authors.initials: AM
authors.lastname: Sprinkart
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Block
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: hans.schild@ukb.uni-bonn.de.
authors.forename: Hans Heinz
authors.initials: HH
authors.lastname: Schild
authors.affiliation: Department of Radiology, Neuroradiology, Sonography and Nuclear Medicine, Hospital of the Barmherzige Brüder Trier, Nordallee 1, 54292 Trier, Germany. Electronic address: w.willinek@bk-trier.de.
authors.forename: Winfried
authors.initials: W
authors.lastname: Willinek
mesh_terms: D000368:Aged; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D011472:Prostatitis / Q000000981:diagnostic imaging*; D011873:Radiology Information Systems; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media
keywords: MRI; PI-RADS; Prostate; Prostate cancer; Prostatitis