Ultra-high-b-value diffusion-weighted MR imaging for the detection of prostate cancer: evaluation in 201 cases with histopathological correlation.

ABSTRACT

PURPOSE: To assess the diagnostic performance of diffusion-weighted magnetic resonance (MR) imaging (DWI) for prostate cancer detection, using different b-values. METHODS: A total of 201 patients who underwent MR imaging before total prostatectomy were evaluated. MR images were independently assessed by three radiologists. Three combinations of sequences were separately evaluated, as follows group 1 [T2-weighted images (T2WI) alone], group 2 (T2WI and DWI with a b-value of 1,000 s/mm2), group 3 (T2WI and DWI with a b-value of 2,000 s/mm2). Whole-mount-section histopathological examination was the reference standard. Areas under the receiver operating characteristic curve (AUCs) and diagnostic performance parameters were determined. RESULTS: The sensitivity, specificity, and AUC for the detection of prostate cancer were as follows 52.2%, 80.7%, and 0.694 in group 1; 61.2%, 82.6%, and 0.755 in group 2; 73.2%, 89.7%, and 0.842 in group 3. Group 3 achieved the highest diagnostic performance, followed by group 2 (P<0.05). In the transition zone, the specificity was lower (P<0.001) for group 2 (82.2%) than for group 1 (86.2%). CONCLUSION: The addition of diffusion-weighted images with a b-value of 2,000 s/mm2 to T2WI can improve the diagnostic performance of MR imaging in prostate cancer detection.