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Prostate volume and PSA density (PSAd) are important in the risk stratification of suspected prostate cancer (Pca). PI-RADS v2.1 allows for determining volume via segmentation or ellipsoid calculation. The purpose of our study was to compare ellipsoid and segmentation volume calculation methods and evaluate if PSAd diagnostic performance is altered. We retrospectively assessed 397 patients (mean age/standard deviation: 63.7/7.4 years) who underwent MRI and prostate biopsy or prostatectomy, with Pca classified by Gleason ≥3 + 4 and ≥4 + 4 disease. Prostate total volumes were determined with ellipsoid calculations (TVe) and with semi-automated segmentation (TVs), along with inter-rater reliability with intraclass correlation coefficient (ICC). PSAd was calculated for TVe and TVs and ROC curves were created to compare performance for Gleason ≥3 + 4 and ≥4 + 4 disease. TVe was significantly higher than TVs (p < 0.0001), with mean TVe = 55.4 mL and TVs = 51.0 mL. ROC area under the curve for PSAd derived with TVe (0.63, 95%CI:0.59–0.68) and TVs (0.64, 95%CI:0.59–0.68) showed no significant difference for Gleason ≥3 + 4 disease (p = 0.45), but PSAd derived with TVs (0.63, 95%CI: 0.58–0.68) significantly outperformed TVe (0.61, 95%CI: 0.57–0.67) for Gleason ≥4 + 4 disease (p = 0.02). Both methods demonstrated excellent inter-rater reliability with TVe with ICC of 0.93(95%CI: 0.92–0.94) and TVs with ICC of 0.98(95%CI: 0.98–0.99). Traditional ellipsoid measurements tend to overestimate total prostate volume compared to segmentation, but both methods demonstrate similar diagnostic performance of derived PSA density for PI-RADS clinically significant disease. For higher grade disease, PSAd derived from segmentation volumes demonstrates statistically significant superior performance. Both methods are viable, but segmentation volume is potentially better. • Traditional ellipsoid measurements overestimate prostate volume versus segmentation. • Both methods derived PSA density have similar performance for Gleason >/=7 disease. • Segmentation method for PSA density outperforms ellipsoid for high grade cancer. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: PSA density (PSAd), an important decision-making parameter for patients with suspected prostate cancer (PCa), is dependent on magnetic resonance imaging prostate volume (PV) estimation. We aimed to compare the accuracy of the ellipsoid and bullet-shaped formulas with manual whole-gland segmentation as reference standard and to evaluate the corresponding PSAd diagnostic accuracy in predicting clinically significant PCa.Materials and Methods: We retrospectively analysed 195 patients with suspected PCa who underwent magnetic resonance imaging and prostate biopsy. Patients with PCa were categorized according to ISUP score. PV and corresponding PSAd were calculated with manual segmentation (mPV and mPSAd) as well as with ellipsoid (ePV and ePSAd) and bullet-shaped (bPV and bPSAd) formulas. Inter and intra-reader reproducibility were assessed with Lin's concordance correlation coefficient and the intraclass correlation coefficient (ICC). A 2-way analysis of variance with post-hoc Bonferroni test was used for assessing PV differences. Predictive values of PSAd calculated with different methods for detecting clinically significant PCa were evaluated by receiver operating characteristic curve analysis and Youden's index.Results: Both intra (ρ = 0.99, ICC = 0.99) and inter-reader (ρ = 0.98, ICC = 0.98) reproducibility were excellent. No significant difference was found between ePV and reference standard (p = 1.00). bPV was significantly different from both (p = 0.00). PSAd (mPSAd/ePSAd cut-off ≥ 0.15, bPSAd cut-off ≥ 0.12) had sensitivity = 69-70%, specificity = 72-75%, areas under the curve = 0.757-0.760 (p = 0.70-0.88).Conclusions: Our work shows that when using bullet-shaped formula, a different PSAd cut-off must be considered to avoid PCa under-diagnosis and inaccurate risk-stratification. [ABSTRACT FROM AUTHOR]

Purpose: Bi-parametric prostate MR (bp-MR) is a valuable tool for detection and characterization of prostate cancer (PCa). Recent studies suggested that PSA-density (PSA-D) in combination with multi-parametric prostate MR as well as bp-MR may achieve a higher diagnostic accuracy than either alone. We aimed to evaluate the diagnostic performance of bp-MR, PSA-D and their combination in biopsy-naïve patients.Methods and Materials: We retrospectively analyzed 334 consecutive patients who underwent prostate MR on a 3T scanner. Only patients (n = 114) who underwent TRUS-biopsy within 30 days following MR with no previous prostate biopsies were considered. Our protocol included T2-weighted and DWI sequences. A Likert score based on PI-RADS v2 was used for bp-MR evaluation. Lesions were graded histopathologically using the ISUP score. We assessed three scenarios: detection of lesions independently of ISUP score (ISUP ≥ 1), detection of both intermediate and clinically significant lesions (ISUP ≥ 2) and detection of clinically significant lesions alone (ISUP ≥ 3). Predictive value of bp-MR and PSA-D was evaluated by ROC curves and logistic regression analysis. A p value < 0.05 was considered statistically significant.Results: In all evaluated scenarios, bp-MR showed a significantly higher predictive power (AUC = 0.87-0.95) compared to the performance of PSA-D (AUC = 0.73-0.79), while their combination (AUC = 0.91-0.95) showed no statistically significant improvement compared to bp-MR alone.Conclusion: Our results confirm that bp-MR is a powerful tool in detection of clinically significant PCa. Contrary to findings in the recent literature, PSA-D does not appear to significantly improve its diagnostic performance. [ABSTRACT FROM AUTHOR]