Background:This prospective study aims to reveal whether the lesion is a benign pathological process or malignant by measuring ADC values under PI-RADSv2.1 guidance on MpMRI examinations. Additionally, the paper evaluates whether there is a correlation between malignant lesions’ pathological grade and ADC values, and whether ADC values provide noninvasive information about prostate cancer aggressiveness. Purpose:To determine the cut-off ADC values that may exist to identify and distinguish between benign and malignant lesions and also identify cancers with an ISUP score≥2 and cancers with an ISUP score1 defined as silent disease. Methods:This study includes 243 patients and they were diagnosed with TRUS-guided cognitive MRI fusion as tissue diagnosis. MpMRI images were evaluated before biopsy according to PI-RADSv2.1 guideline by a radiologist. Three groups which are benign prostatic tissue, prostatitis, prostate cancer, were obtained according to the histopathological results. Results: When the cut-off value for ADC is 780 x10-3, sensitivity was 80%. When the cut-off value was taken as 668 x10-3, the sensitivity was found to be 72% and specificity 62%. When the cut-off ADC value was taken as 647 x10-3, the sensitivity was 83% and the specificity was 48.5%. ADC values varied significantly according to ISUP groups [p= 0.003]. It was determined that ISUP 1 group was significantly higher than each of the other groups. ADC group mean values did not show a statistically significant difference between Group 2,3,4 and 5. Conclusion:ADC value shows significant potential, and may it improve the diagnostic accuracy.

Purpose: To evaluate the correlation between PI-RADSv2.1 and International Society of Urologic Pathologists (ISUP) score for patients who underwent multiparametric-MRI(MpMRI) prior to transrectal ultrasound (TRUS) guided cognitive fusion biopsy (CF-Bx). And to investigate inter-observer agreement of PI-RADSv2.1. Methods: Patients who underwent MpMRI of prostate prior to first TRUS-guided CF-Bx, were included in this prospective study. MpMRI examinations were evaluated by two radiologists before biopsy according to the PI-RADSv2.1. Interobserver agreement was recorded and the final PI-RADS categorization was performed by consensus. Correlation of histopathological results with PI-RADSv2.1 score was evaluated. Lesions with Gleason Score(GS)≥6 were considered as prostate cancer (PCa). Results: A total of 84 patients with 106 lesions were included in the study. The ratio of PCa in the PI-RADS groups 1,2,3,4,5 was 0%, 0%, 22.2%, 56%, 94.45%, respectively. There was a positive correlation with a value of 0.814 between the PI-RADSv2.1 and the ISUP score. When PI-RADS≥3 is accepted as the cut-off value in peripheral zone(PZ) and the whole gland, the NPV for malignancy was 100.00%. For PI-RADS ≥4, it was 76.47% for PZ, and 80.65% for the whole gland. For the whole gland; sensitivity, specificity, and PPV of the PI-RADS≥3 were 100%, 12.9%, and 44.33%, respectively; for PI-RADS≥4, these values were 72.09%, 80.65%, and 72.09% respectively. Without applying cut-off values, the interobserver agreement for PI-RADS score was κappa:0.562. Conclusions: PI-RADSv2.1 was created in the framework of v2 to facilitate to evaluate MpMRI and to increase interobserver agreement. We believe that further studies will be necessary.