title: Diffusion-weighted imaging predicts upgrading of Gleason score in biopsy-proven low grade prostate cancers.
abstract: OBJECTIVE
  To analyse whether diffusion-weighted imaging (DWI) predicts Gleason score (GS) upgrading in biopsy-proven low grade prostate cancer (PCa).
  
  
  METHODS
  A total of 132 patients who had biopsy-proven low grade (GS < 7) PCa, 3T DWI results, and surgical confirmation were retrospectively included in the study. Clinical variables (prostate-specific antigen, greatest percentage of cancer in a biopsy core and percentage of positive cores) and DWI variables (minimum apparent diffusion coefficient [ADCmin] and mean ADC [ADCmean]) were evaluated. ADCminwas measured, by two independent, blinded readers, using a region of interest (ROI) of 5-10 mm2at the area of lowest ADC value within a cancer, while ADCmeanwas measured using an ROI covering more than half of a cancer. Logistic regression and receiver-operating characteristic curve analyses were performed.
  
  
  RESULTS
  The rate of GS upgrading was 46.1% (61/132). In both univariate and multivariate analyses, ADCminand ADCmeanwere persistently significant for predicting GS upgrading (P < 0.05), whereas clinical variables were not (P > 0.05). In both readers' results, the area under the curve (AUC) of ADCminwas significantly greater than that of ADCmean(reader 1: AUC 0.760 vs 0.711; P < 0.001; reader 2: AUC 0.752 vs 0.714; P = 0.003).
  
  
  CONCLUSIONS
  Our results showed that DWI may predict GS upgrading of biopsy-proven low grade PCa. The variable ADCminin PCa may perform better than ADCmean.
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sung Yoon
authors.identifier: http://orcid.org/0000-0003-0996-7595
authors.initials: SY
authors.lastname: Park
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young Taik
authors.initials: YT
authors.lastname: Oh
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dae Chul
authors.initials: DC
authors.lastname: Jung
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Nam Hoon
authors.initials: NH
authors.lastname: Cho
authors.affiliation: Department of Urology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young Deuk
authors.initials: YD
authors.lastname: Choi
authors.affiliation: Department of Urology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Koon Ho
authors.initials: KH
authors.lastname: Rha
authors.affiliation: Department of Urology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sung Joon
authors.initials: SJ
authors.lastname: Hong
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011237:Predictive Value of Tests; D011467:Prostate / Q000000981:diagnostic imaging* / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D012189:Retrospective Studies
keywords: Gleason score; diffusion-weighted imaging; prostate cancer; upgrading