Wash-in rate on the basis of dynamic contrast-enhanced MRI: usefulness for prostate cancer detection and localization.

PURPOSE To evaluate the usefulness of the wash-in rate based on dynamic contrast-enhanced (DCE) MRI for the detection and localization of prostate cancer. MATERIALS AND METHODS In 53 patients, the wash-in rate was measured in the cancer area and in three normal areas (the peripheral zone, inner portion of the transitional zone, and outer portion of the transitional zone). On the basis of these data, parametric imaging was generated and then its accuracy for cancer detection and location was evaluated compared to that of T2-weighted imaging without the use of an endorectal coil. For that purpose the entire prostate was divided into 18 segments. RESULTS The wash-in rate value was greater in cancer tissue (9.2/second) than in three normal tissues (3.3/second, 6.7/second, and 3.2/second, respectively; P<0.001). The sensitivity and specificity were greater on parametric imaging of the wash-in rate compared to T2-weighted imaging in the entire prostate (96% and 82% vs. 65% and 60%, respectively) and the peripheral zone (96% and 97% vs. 75% and 53%; P<0.05). In the transitional zone, the sensitivity was greater on parametric imaging (96%) than on T2-weighted imaging (45%; P=0.016), but the specificity was similar (51% vs. 73%; P=0.102). CONCLUSION The wash-in rate based on DCE-MRI is a useful parameter for prostate cancer detection and localization.