Prostate cancer discrimination in the peripheral zone with a reduced field-of-view T-2-mapping MRI sequence

Abstract

Objectives: To evaluate the performance of T-2 mapping in discriminating prostate cancer from normal prostate tissue in the peripheral zone using a practical reduced field-of-view MRI sequence requiring less than 3 minutes of scan time. Materials and methods: Thirty-six patients with biopsy-proven peripheral zone prostate cancer without prior treatment underwent routine multiparametric MRI at 3.0 T with an endorectal coil. An Inner-Volume Carr-Purcell-Meiboom-Gill imaging sequence that required 2.8 minutes to obtain data for quantitative T-2 mapping covering the entire prostate gland was added to the routine multiparametric protocol. Suspected cancer (SC) and suspected healthy (SH) tissue in the peripheral zone were identified in consensus by three radiologists and were correlated with available biopsy results. Differences in mean T-2 values in SC and SH regions-of-interest (ROIs) were tested for significance using unpaired Student's two-tailed t-test. The area under the receiver operating characteristic curve was used to assess the optimal threshold T-2 value for cancer discrimination. Results: ROI analyses revealed significantly (p < 0.0001) shorter T-2 values in SC (85.4 +/- 12.3 ms) compared to SH (169.6 +/- 38.7 ms). An estimated T-2 threshold of 99 ms yielded a sensitivity of 92% and a specificity of 97% for prostate cancer discrimination. Conclusions: Quantitative values derived from this clinically practical T-2-mapping sequence allow high precision discrimination between healthy and cancerous peripheral zone in the prostate.