Combined diffusion-weighted and dynamic contrast-enhanced MRI for prostate cancer diagnosis--correlation with biopsy and histopathology.

PURPOSE To determine whether the combination of diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI provides higher diagnostic sensitivity for prostate cancer than each technique alone. MATERIALS AND METHODS Fourteen patients with a clinical suspicion of prostate cancer underwent endorectal MRI on a 1.5T scanner prior to transrectal ultrasound (TRUS)-guided biopsies. The average values of the apparent diffusion coefficient (ADC, calculated from b-values of 0 and 600), K(trans), v(e), maximum gadolinium (Gd) concentration, onset time, mean gradient, and maximum enhancement were determined. Correlation with histology was based on biopsy (six patients) and prostatectomy specimen (eight patients) results. The Tukey-Kramer test was used for statistical analysis. RESULTS The average values of all MRI parameters, except v(e) and maximum Gd concentration, showed significant differences between tumor and normal prostate. The sensitivity and specificity values were respectively 54% (35-72%) and 100% (95-100%) for the ADC data, and 59% (39-77%) and 74% (63-83%) for the DCE data. When both ADC and DCE results were combined, the sensitivity increased to 87% (68-95%) and specificity decreased to 74% (62-83%). CONCLUSION All but two DW- and DCE-MRI parameters showed significant differences between tumor and normal prostate. Combining both techniques provides better sensitivity, with a small decrease in specificity.