Cancer - Prostate(구연) (NP-011) PI-RADS 3 병변에서 임상적으로 의미있는 전립선암 진단을 위한 biparametric MRI를 이용한 제한확산 정량화 부산대학교 의과대학 비뇨기과학교실 박지훈, 강병진, 박시균, 이권경, 김경환, 구자윤, 하홍구 Purpose PI-RADS 3 lesions are equivocal for the presence of clinically significant prostate cancer(CS-PCa). Several guidelines recommend biopsy for PI-RADS 3 lesions, but the specificity is too low to avoid unnecessary biopsies or diagnosis of insignificant PCa. More detailed diagnostic criteria are needed to differentiate PCa from benign prostate and CS-PCa from PCa in PI-RADS 3 lesions. Materials and Methods This retrospective study included 141 patients who had consecutively undergone biparametric MRI(bpMRI) in combination with TRUS-MR fusion biopsy between June 2016 and June 2019. PI-RADS 3 lesions on bpMRI were indicated by experienced radiologists according to PI-RADS v2, marked as a region-of-interest(ROI) and targeted by TRUS-MR fusion biopsy. ADC values were calculated for a pair of b values: 50 and 1400 s/mm2. ADC values of ROIs were recoreded by averaging the values measured at least three times each by two urologists. The size of ROIs was chosen to be as large as possible and with minimal contamination from normal tissue. CS-PCa was defined as ISUP grade of 2 or greater. Result Of the 194 lesions indicated and biopsied, 150(77.3%) were on peripheral zone(PZ) and 44(22.7%) on transitional zone(TZ). In PZ, 17(11.3%) lesions were diagnosed with PCa, including 9(6.0%) with CS-PCa, and in TZ, 4(9.1%) and 2(4.5%) were detected with PCa and CS-PCa, respectively. Because PCa diagnosis rate was too low in TZ, receiver operating characteristic(ROC) curve analysis was performed only for PZ. Area under curve (AUC) of ADC value for detecting PCa and CS-PCa in PZ were 0.806 (p<0.0001) and 0.736(p=0.033). Optimal ADC cut-off value(x10-3 mm2/s) was 0.791(sensitivity 76.47%, specificity 84.21%) and 0.763(sensitivity 66.67%, specificity 84.40%) for detecting PCa and CS-PCa, respectively. Conclusion Quantification of the diffusion limitation in patients with PI-RADS 3 lesions in PZ may play a predictive role in the detection of PCa and CS-PCa. keywords : PI-RADS 3 lesion, clinically significant prostate cancer, ADC value