Diagnostic efficacy of b value (2000 s/mm(2)) diffusion-weighted imaging for prostate cancer: Comparison of a reduced field of view sequence and a conventional technique

Objectives: To compare high b value (2000 s/mm(2)) reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) with a conventional DWI sequence in terms of image quality, as well as diagnostic performance concerning prostate cancer (PCa) detection and tumor staging at 3T. Methods: Sixty-one patients underwent rFOV DWI and conventional DWI due to clinical suspicious of PCa were retrospectively recruited. Imaging qualities were evaluated qualitatively and quantitatively by two blinded radiologists. Thirty-two subjects with detailed pathology reports were further analyzed for diagnostic efficacy using the Prostate Imaging Reporting and Data System (PI-RADS) version 2. The PCa detection rate, sensitivity, specificity, and PI-RADS staging changes were compared between the DWI sequences. Results: Qualitative evaluation regarding image quality was significantly better in rFOV DWI than in the conventional DWI (all P < 0.05). ADC contrast with rFOV DWI was rated significantly higher than the conventional DWI in both peripheral zone (PZ) and transition zone (TZ) (P = 0.001 for PZ, and P = 0.003 for TZ). Regarding diagnostic efficacy, rFOV DWI yielded higher tumor detection, sensitivity and the area under the curve (AUC) than the conventional DWI (all P < 0.05), except the AUC in the PZ for one reader (P = 0.262). Conventional DWI achieved slightly higher specificity for the PZ and TZ but with no significant difference except for one reader in the PZ (P = 0.009). Conclusion: The rFOV DWI could offer improved image quality and yielded better diagnostic performance in terms of higher tumor detection rate and relatively precise staging for PCa compared to the conventional sequence.