Clinical impact of ultra-high b-value (3000 s/mm(2)) diffusion-weighted magnetic resonance imaging in prostate cancer at 3T: comparison with b-value of 2000 s/mm(2)

Objective: High b-value diffusion-weighted imaging (hDWI) with a b-value of 2000 s/mm(2) provides insufficient image contrast between benign and malignant tissues and an overlap of apparent diffusion coefficient (ADC) between Gleason grades (GG) in prostate cancer (PC). We compared image quality, PC detectability, and discrimination ability for PC aggressiveness between ultra-high b-value DWI (uhDWl) of 3000 s/mm(2) and hDWI. Methods: The subjects were 49 patients with PC who underwent 3T multiparametric MRI. Single-shot echoplanar DWI was acquired with b-values of 0, 2000, and 3000 s/mm(2). Anatomical distortion of prostate (AD), signal intensity of benign prostate (PSI), and lesion conspicuity score (LCS) were assessed using a 4-point scale; and signal-to-noise ratio, contrast-to-noise ratio, and mean ADC (x10(-3) mm(2)/s) of lesion (IADC) and surrounding benign region (bADC) were measured. Results: PSI was significantly lower in uhDWl than in hDWI (p < 0.001). AD, LCS, signal-to-noise ratio, and contrast-to-noise ratio were comparable between uhDWl and hDWI (all p > 0.05). In contrast, IADC was significantly lower than bADC in both uhDWI and hDWI (both p < 0.001). In comparison of IADC between tumors of <= GG2 and those of >= GG3, both uhDWI and hDWI showed significant difference (p = 0.007 and p = 0.021, respectively). AUC for separating tumors of <= GG2 from those of >= GG3 was 0.731 in hDWI and 0.699 in uhDWl (p = 0.161). Conclusion: uhDWl suppressed background signal better than hDWI, but did not contribute to increased diagnostic performance in PC. Advances in knowledge: Compared with hDWI, uhDWI could not contribute to increased diagnostic performance in PC.