Efficacy evaluation of apparent diffusion coefficient from diffusion weighted imaging in identifying intermediate and high grade prostate cancer

Abstract

Objective To evaluate the utility of apparent diffusion coefficient (ADC) values from DWI in identifying intermediate and high grade prostate cancer (patients harboring Gleason 4 and/or 5 components in their radical prostatectomy specimens). Methods We retrospectively analyzed the DWI of 54 patients with biopsy-proven prostate cancer and biopsy Gleason score (GS) ≤3+3=6. These patients were divided into two groups, intermediate and high grade prostate cancer (patients harboring Gleason 4 and/or 5 components in their radical prostatectomy specimens) and low-grade prostate cancer (patients not harboring Gleason 4 and/or 5 components in their radical prostatectomy specimens). ROIs were drawn on areas of the most suspicious lesion on T2WI and the ADC values were calculated. The ADC values of the two groups were compared to determine whether there were differences between them with independent-sample t test. Receiver operating characteristic (ROC) curve was used to determine the ability of ADC values in differentiating intermediate/high grade prostate cancer from low-grade prostate cancer. Results Twenty-eight patients had intermediate and high grade prostate cancer while the other twenty-six ones had low-grade prostate cancer. Significant differences were found for the ADC values of these two groups [(0.905±0.162) ×10-3mm2/s vs. (1.143±0.165)×10-3mm2/s, t=5.361,P<0.01]. The area under the ROC curve of ADC in differentiating intermediate and high grade prostate cancer from low-grade prostate cancer was 0.861, with sensitivity of 88.5% and specificity of 67.9% at the cut-off of 1.000 × 10-3mm2/s. Conclusion The ADC values of suspicious areas in prostate contribute to identify intermediate/high grade prostate cancer in patients with a GS≤3+3=6 on biopsy. Key words: Prostate neoplasms; Magnetic reasonance imaging; Comparative study