Biparametric versus multiparametric MRI in the diagnosis of prostate cancer

Background: Since multiparametric magnetic resonance imaging (mp-MRI) of the prostate exceeds 30 min, minimizing the evaluation time of significant (Gleason scores > 6) prostate cancer (PCa) would be beneficial. A reduced protocol might be sufficient for the diagnosis. Purpose: To study whether a short unenhanced biparametric MRI (bp-MRI) matches mp-MRI in detecting significant PCa. Material and Methods: A total of 204 men (median age, 65 years; mean +/- SD, 64.1; range 45-75 years; median serum PSA level, 14 ng/mL; range, 2.2-120 ng/mL; median prostate volume, 60 mL; range, 23-263 mL) fulfilled the criteria for being enrolled. They underwent mp-MRI and prostate biopsy from January through June 2014. Of the included patients, 9.3% underwent prostatectomy, 90.7% had TRUS-bx, and 10.8 had MRI-targeted TRUS-bx. Two radiologists separately assessed the mp-MRI examination (T2-weighted [T2W] imaging, diffusion-weighted imaging [DWI], apparent diffusion coefficient map [ADC-map] and dynamic contrast-enhanced imaging [DCE]). Two months later, the bp-MRI version (T2W imaging, DWI, and ADC-map) was evaluated. Results: Reader 1: Assessing mp-MRI: 0 false negatives, sensitivity of 1, and specificity 0.04. Assessing bp-MRI: four false negatives, sensitivity of 0.94, and specificity 0.15. Reader 2: Assessing mp-MRI: five false negatives, sensitivity of 0.93, and specificity 0.16. Assessing bp-MRI: three false negatives, sensitivity of 0.96, and specificity 0.15. Intra-reader agreement Cohen's Kappa (kappa) was 0.87 for reader 1 (95% confidence interval [CI], 0.83-0.92) and 0.84 for reader 2 (95% CI 0.78-0.89). Conclusion: Bp-MRI is as good as mp-MRI at detecting PCa. A large prospective study seems to be strongly warranted.