To stratify patients with PI-RADSv2 category 3 to define the correct diagnostic work-up (biopsy or follow-up), quantitatively analyzing mpMRI parameters (ADC, k-trans, K-ep and ve). Among 1272 men who underwent mpMRI, we retrospectively enrolled 98 patients treated with radical prostatectomy. Furthermore, we selected 100 negative patients. The 198 mpMRI exams were randomly, blindly reviewed by two radiologists. 95 PI-RADSv2 category 3 were found and quantitatively analyzed. ROC and AUC were determined to identify a cut-off value to define which PI-RADS 3 lesion should be biopsied. Quantitative imaging represents a tool to objectively stratify patients classified as PI-RADSv2 category 3.