title: Apparent diffusion coefficient ratio correlates significantly with prostate cancer gleason score at final pathology.
abstract: OBJECTIVE
  To evaluate the correlation between apparent diffusion coefficient measurements (ADCtumor and ADCratio ) and the Gleason score from radical prostatectomy specimens.
  
  
  METHODS
  Seventy-one patients with clinically localized prostate cancer scheduled for radical prostatectomy were prospectively enrolled. Multiparametric magnetic resonance imaging (MRI) was performed prior to prostatectomy and mean ADC values from both cancerous (ADCtumor ) and benign (ADCbenign ) tissue were measured to calculate the ADCratio (ADCtumor divided by ADCbenign ). The ADC measurements were correlated with the Gleason score from the prostatectomy specimens.
  
  
  RESULTS
  The association between ADC measurements and Gleason score showed a significant negative correlation (P < 0.001) with Spearman's rho for ADCtumor (-0.421) and ADCratio (-0.649). There was a statistically significant difference between ADC measurements and the Gleason score for all tumors (P = 0.001). Receiver operating characteristic curve analysis showed an overall area under the curve (AUC) of 0.73 (ADCtumor ) to 0.80 (ADCratio ) in discriminating Gleason score 6 from Gleason score ≥7 tumors. The AUC changed to 0.72 (ADCtumor ) and 0.90 (ADCratio ) when discriminating Gleason score ≤7(3+4) from Gleason score ≥7(4+3).
  
  
  CONCLUSIONS
  ADC measurements showed a significant correlation with tumor Gleason score at final pathology. The ADCratio demonstrated the best correlation compared to the ADCtumor value and radically improved accuracy in discriminating Gleason score ≤7(3+4) from Gleason score ≥7(4+3) tumors.
authors.affiliation: Department of Urology, Herlev University Hospital, Herlev, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Boesen
authors.affiliation: Department of Radiology, Herlev University Hospital, Herlev, Denmark.
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Chabanova
authors.affiliation: Department of Radiology, Herlev University Hospital, Herlev, Denmark.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Løgager
authors.affiliation: Department of Pathology, Herlev University Hospital, Herlev, Denmark.
authors.forename: Ingegerd
authors.initials: I
authors.lastname: Balslev
authors.affiliation: Department of Radiology, Herlev University Hospital, Herlev, Denmark.
authors.forename: Henrik S
authors.initials: HS
authors.lastname: Thomsen
mesh_terms: D000368:Aged; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D015588:Observer Variation; D011471:Prostatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
keywords: Gleason score; diffusion-weighted MRI; prostate cancer; prostatectomy