Do apparent diffusion coefficient (ADC) values obtained using high b-values with a 3-T MRI correlate better than a transrectal ultrasound (TRUS)-guided biopsy with true Gleason scores obtained from radical prostatectomy specimens for patients with prostate cancer?

Objective: To investigate the usefulness of apparent diffusion coefficient (ADC) values in predicting true Gleason scores from radical prostatectomy specimen (tGS), compared with systematic transrectal ultrasound (TRUS)-guided biopsy GS (bGS). Materials and methods: One hundred and five patients with biopsy-proven prostate cancer underwent preoperative DWI (b-values of 0, 1000, and 2000 s/mm(2)) of 3-T MRI. The mean and minimum ADCs of visible tumors were calculated for either of a pair of b-values: 0 and 1000 s/mm(2) (ADC(1000)), or 0 and 2000 s/mm(2) (ADC(2000)), and relationships between the four ADC parameters and tGS evaluated for the peripheral zone (PZ) and transition zone (TZ). For multiple tumors, the dominant tumor's GS and ADCs were estimated for cancer aggressiveness assessment by computing ROC curves. Results: Significant negative correlations were observed between tGS and mean ADC(1000), mean ADC(2000), minimum ADC(1000), and minimum ADC(2000) (r = -0.41, -0.39, -0.39, and -0.37, respectively) of 100 visible PZ tumors and 66 visible TZ tumors (r = -0.40, -0.42, -0.29, and -0.21, respectively). For distinguishing high-grade from low/intermediate-grade PZ lesions, the areas under the curve (AUCs) of mean ADC(1000) (0.751), mean ADC(2000) (0.710), minimum ADC(1000) (0.768), and minimum ADC(2000) (0.752) were similar to that of the highest bGS (0.708) (p = 0.61, p = 0.98, p = 0.47, and p = 0.60, respectively). For distinguishing high-grade from low/intermediate-grade TZ lesions, AUCs of mean ADC(1000) (0.779), and mean ADC(2000) (0.811) were similar to that of the highest bGS (0.805) (p = 0.83 and p = 0.97). Conclusion: Tumor ADCs obtained with high b-values could predict prostate cancer aggressiveness as effectively as systematic TRUS-guided biopsy. (C) 2013 Elsevier Ireland Ltd. All rights reserved.