Predictive value of the combined use of PHID and ADC parameters for prostate biopsy decision-making in PI-RADS 3 lesions

To evaluate the diagnostic accuracy of combining the Prostate Health Index density (PHID) with apparent diffusion coefficient (ADC) parameters in patients with multiparametric magnetic resonance imaging (mp-MRI) showing Prostate Imaging Reporting and Data System Version 2.1 (PI-RADS v2.1) score 3 lesions. A retrospective analysis was conducted in 207 patients with PI-RADS 3 lesions who underwent mp-MRI and had tPSA, fPSA, and p2PSA measured prior to prostate biopsy at a single center from January 2019 to December 2024. ADC values were assessed on a single slice of mp-MRI using region-of-interest (ROI) analysis. Logistic regression analyses and receiver operating characteristic (ROC) curves were used to evaluate predictors of prostate cancer (PCa) and clinically significant prostate cancer (csPCa). DeLong tests were performed to compare AUCs, and multivariable logistic regression was used to assess independent predictors. Of the 207 men included, 69 (33.3%) were diagnosed with PCa and 37 (17.9%) with csPCa. Suspicious PI-RADS 3 lesions in the peripheral zone exhibited significantly lower ADC-lesion and ADC-average values in both the PCa and csPCa groups ( p < 0.001 and p = 0.027, respectively). ROC analysis showed that PHID and ADC parameters were significant predictors of PCa and csPCa ( p < 0.001). When combining PHID with ADC parameters using optimal cut-off values, the best performance was achieved by PHID & ADC-peri-lesion, with an AUC of 0.846 for PCa and 0.879 for csPCa. DeLong tests confirmed that the combined PHID-ADC approach had significantly higher AUC than PHID alone ( p = 0.004) and ADC-peri-lesion alone ( p = 0.027) for csPCa prediction. Multivariable analysis confirmed PHID (OR = 1.048, p < 0.001) and ADC-peri-lesion (OR = 3.214, p < 0.001) as independent predictors of csPCa. The combined use of PHID and ADC parameters improves PCa and csPCa detection in patients with PI-RADS 3 lesions. ADC parameters in suspicious PI-RADS 3 lesions of the peripheral zone demonstrate superior diagnostic value. PHID and ADC parameters are independent predictors of csPCa even after multivariable adjustment.