Value of Dynamic Contrast-Enhanced (DCE) MR Imaging in Peripheral Lesions in PI-RADS-4 Patients.

OBJECTIVE: To assess the impact of dynamic contrast-enhanced imaging (DCE) in mp-MRI on prostate cancer (PCa) detection in a large patient cohort assigned to PI-RADS category 4. METHOD: This retrospective, single center cohort study includes 193 consecutive patients with PI-RADS assessment category 4 in mp-MRI (T2WI, DWI, DCE) at 3 T with targeted plus systematic biopsy combined as the reference standard. The detection of prostate cancer with and without the use of DCE was compared. RESULTS: Overall, the PCa detection rate in PI-RADS-4 patients was 62 % (119/193) with DCE and 52 % (101/193) without the inclusion of lesions upgraded on the basis of DCE. 48 % (92/193) had clinically significant PCa (csPCa; Gleason score ≥ 3 + 4 = 7) and 40 % (78/193) without use of DCE. 38 of the 193 patients (20 %) had peripheral lesions upgraded from PI-RADS category 3 to an overall PI-RADS category 4 due to focal positive DCE findings. Of these 38 patients, 18 had PCa including 14 with csPCa. Thus, 15 % (18/119) of the patients with PCa and 15 % (14/92) of the patients with csPCa were detected only based on additional DCE information. CONCLUSION: DCE prevents underestimation and misclassification of a significant number of cases of peripheral csPCa and might improve detection rates in PI-RADS-4 patients. The current PI-RADS decision rules regarding upgrading PI-RADS-3 lesions to category 4 due to positive DCE imaging are useful for PCa detection. KEY POINTS: · Positive peripheral DCE upgraded 20 % of patients in PI-RADS category 4 from category 3.. · Clinically significant PCa was found in almost 40 % of upgraded, peripheral PIRADS-3-lesions.. · 15 % of all csPCa in PI-RADS-4-patients was detected in DCE-upgraded lesions.. · In 7 % of all PI-RADS-4-cases csPCa would had been underestimated without DCE upgrade.. CITATION FORMAT: · Ullrich T, Quentin M, Arsov C et al. Value of Dynamic Contrast-Enhanced (DCE) MR Imaging in Peripheral Lesions in PI-RADS-4 Patients. Fortschr Röntgenstr 2020; 192: 441 - 447.

Risk Stratification of Equivocal Lesions on Multiparametric Magnetic Resonance Imaging of the Prostate.

PURPOSE: We systematically analyzed the records of patients with PI-RADS™ (Prostate Imaging Reporting and Data System) 3 lesions, which are called equivocal according to PI-RADS version 2, using prostate multiparametric magnetic resonance imaging and magnetic resonance imaging targeted biopsies. Systematic transrectal ultrasound guided biopsies served as the reference standard. MATERIALS AND METHODS: A total of 120 consecutive patients were retrospectively included in the study. In these patients the overall PI-RADS score was 3 after 3 Tesla T2-weighted imaging, diffusion weighted imaging and dynamic contrast enhanced multiparametric magnetic resonance imaging as well as subsequent targeted magnetic resonance imaging/ultrasound fusion guided biopsies plus systematic 12-core transrectal ultrasound guided biopsies. The study end points were the prostate cancer detection rate, the Gleason score distribution, the prostate cancer location and risk stratification by subgroup analyses. RESULTS: Prostate cancer was detected in 13 of 118 patients for a detection rate of 11%, including 5 patients (4.2%) with a Gleason score of 3 + 4 = 7 or greater. Three of the 212 lesions (1.4%) in the transition zone and 6 of the 64 (9.4%) in the peripheral zone were positive for prostate cancer. Multiparametric magnetic resonance imaging revealed patterns of peripheral prostatitis combined with diffuse stromal hyperplasia in 54% of the patients with prostate cancer. Prostate volume was significantly lower in patients with prostate cancer (p = 0.015) but differences in prostate specific antigen levels were not statistically significant (p = 0.87). Prostate specific antigen density was higher in patients with prostate cancer (0.19 vs 0.12 ng/ml/ml). CONCLUSIONS: Low grade prostate cancer (Gleason score 3 + 3 = 6) can develop in patients with an overall PI-RADS score of 3. Prostate cancer with a Gleason score of 3 + 4 = 7 or greater can be detected by multiparametric magnetic resonance imaging with a high degree of certainty. Gleason score 4 + 3 = 7 or greater prostate cancer is unlikely in PI-RADS 3 lesions. Therefore, these patients should primarily undergo followup multiparametric magnetic resonance imaging. In patients with a combination of multiparametric magnetic resonance imaging aspects of extensive prostatitis and diffuse stromal hyperplasia low prostate volume and/or high prostate specific antigen density biopsy might be considered.