DWI of Prostate Cancer: Optimalb-Value in Clinical Practice
Aim. To compare the diagnostic performance of diffusion weighted imaging (DWI) usingb-values of 1000 s/mm2and 2000 s/mm2at 3 Tesla (T) for the evaluation of clinically significant prostate cancer.Matherials and Methods. Seventy-eight prostate cancer patients underwent a 3T MRI scan followed by radical prostatectomy. DWI was performed usingb-values of 0, 1000, and 2000 s/mm2and qualitatively analysed by two radiologists. ADC maps were obtained atb-values of 1000 and 2000 s/mm2and quantitatively analyzed in consensus.Results. For diagnosis of 78 prostate cancers the accuracy of DWI for the young reader was significantly greater atb= 2000 s/mm2for the peripheral zone (PZ) but not for the transitional zone (TZ). For the experienced reader, DWI did not show significant differences in accuracy betweenb-values of 1000 and 2000 s/mm2. The quantitative analysis in the PZ and TZ was substantially superimposable between the twob-values, albeit with a higher accuracy with ab-value of 2000 s/mm2.Conclusions. With ab-value of 2000 s/mm2at 3T both readers differentiated clinical significant cancer from benign tissue; higherb-values can be helpful for the less experienced readers.