title: Clinical utility of apparent diffusion coefficient (ADC) values in patients with prostate cancer: can ADC values contribute to assess the aggressiveness of prostate cancer?
abstract: OBJECTIVE
  To retrospectively evaluate the relationship between apparent diffusion coefficient (ADC) values and Gleason score (GS) in prostate cancer.
  
  
  METHODS
  A total of 60 patients who underwent radical prostatectomy for clinically localized prostate cancer were selected for this study. Diffusion-weighted magnetic resonance (MR) images were obtained using a 1.5 T system. ADC values were analyzed between three groups: GS of 6 or less (n = 7); GS of 7 (n = 37); and GS of 8 or higher (n = 16). ADC values of the three GS groups were statistically analyzed in order to determine the relationship with GS. In the 37 patients with GS = 7 the difference in ADC values between GS 3+4 and GS 4+3 was analyzed.
  
  
  RESULTS
  Median ADC values (10⁻³ mm² /s) of the three GS groups were 1.04 (GS = 6 or less), 0.867 (GS = 7), and 0.729 (GS = 8 or higher). Although there was considerable overlap among the groups, the differences in ADC were statistically significant (P < 0.0001). There was a significant inverse correlation between GS and ADC values (z = -0.437, P < 0.0005). Median ADC values (10⁻³ mm² /s) of GS 3+4 and GS 4+3 patients were 0.88 and 0.814, respectively (P < 0.05).
  
  
  CONCLUSIONS
  ADC values showed a negative correlation with GS. Pathologically, however, there was considerable intrasubject heterogeneity.
authors.affiliation: Department of Diagnostic Radiology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan. itou4725@yahoo.co.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Itou
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Narumi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Nishizawa
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tsukuma
mesh_terms: D000368:Aged; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity