Clinical utility of apparent diffusion coefficient (ADC) values in patients with prostate cancer: Can ADC values contribute to assess the aggressiveness of prostate cancer?

Purpose 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). Conclusion ADC values showed a negative correlation with GS. Pathologically, however, there was considerable intrasubject heterogeneity. J. Magn. Reson. Imaging 2011;33:167–172. © 2010 Wiley-Liss, Inc.