Purpose: Recently, new magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) techniques and imaging features of Prostate Imaging and Report and Data System (PI-RADS) 4 or 5 have been reported. The aim of this study was to validate the outcomes of new TRUS-guided biopsy techniques for cancer detection in patients with PI-RADS 4 or 5. Methods: Between June 2018 and November 2018, 94 men underwent TRUS-guided biopsy after PI-RADS 4 (n = 59) or 5 (n = 35) was categorized as an index lesion on MRI. For PI-RADS 4 group, target biopsy was performed in 5 and combination biopsy (target and systematic biopsies) was in 54. For PI-RADS 5 group, target biopsy was performed in 19 and combination biopsy was in 16. Target to combination biopsy ratios and significant cancer detection rates (CDRs) were compared between the groups. Significant cancer was defined as a Gleason score ≥ 7 tumor. Standard reference was biopsy examination. Fisher's exact were used for statistical analysis. Results: Target to combination biopsy ratios was 5:54 in the PI-RADS 4 group and 19:16 in the PI-RADS 5 group (P < 0.0001). The significant CDR of the target biopsy were 42.4% (25/59) in the PI-RADS 4 group and 82.6% (29/35) in the PI-RADS 5 group (P = 0.0002). The significant CDR of combination biopsy was 44.1% (26/59) in the PI-RADS 4 group and 85.7% (30/35) in the PI-RADS 5 group (P < 0.0001). Conclusion: New TRUS biopsy techniques provides high significant CDR patients with PI-RADS 4 or 5. Therefore, TRUS should be performed prior to fusion or in-bore biopsy to determine if these categories are visible.

Purpose: To assess the value of systematic biopsy added to target biopsy for detecting significant cancer in men with Prostate Imaging and Reporting and Data System 5 (PI-RADS 5). Methods: Between March 2014 and November 2018, 186 men had a PI-RADS 5 categorized as an index lesion on magnetic resonance imaging prior to transrectal ultrasound (TRUS)-guided biopsy. Of these patients, 135 (group I) underwent target biopsy alone because of good depiction. The remaining 51 (group II) underwent target and systematic biopsies because of poor depiction. Significant cancer detection rates (CDRs) were compared between the groups. Which type of biopsies contributed to detecting significant cancer was evaluated in the group II. Results: Significant CDRs of the target biopsy were 67.4% (91/135) in the group I and 47.1% (24/51) in the group II (P=0.0173). However, when systematic biopsy was added to target biopsy, the significant CDR of the group II increased to 52.9% (27/51) (P=0.0900). Of the 27 significant cancers missed by target biopsy in the group II, three were detected by systematic biopsy alone. Moreover, systematic biopsy detected higher Gleason scores in two cases than target biopsy. Conclusion: Systematic biopsy contributes to detecting additional significant cancers in men with PI-RADS 5 partially visible on TRUS.

Objectives: Accurate pre-operative prediction of risk stratification using a non-invasive imaging tool is clinically important for planning optimal treatment strategies, particularly in early-stage endometrial cancer (EC). This study aimed to investigate the utility of apparent diffusion coefficient (ADC) histogram analysis in evaluating the pathological characteristics and risk stratification in patients with Stage I EC. Methods: Between October 2009 and December 2014, a total of 108 patients with surgically proven Stage I EC (endometrioid type = 91; non-endometrioid type = 17) excluding stage ≥II that underwent preoperative 3T-diffusion-weighted imaging without administration of contrast medium were enrolled in this retrospective study. Risk stratification was divided into four risk categories based on the ESMO-ESGO-ESTRO Guidelines: low, intermediate, high-intermediate, and high risk. The ADC histogram parameters (minimum, mean [ADCmean], 10th–90th percentile, and maximum [ADCmax]) of the tumor were generated using an in-house software. The ADC histogram parameters were compared between patients with endometrioid type and non-endometrioid type, between Stage IA and IB, between histological grades, and evaluated for differentiating non-high risk group from high risk group. Inter-reader agreement for tumor ADC measurements was also evaluated. Statistical analyses were performed using the Student’s t-test, Mann–Whitney U test, receiver operating characteristics (ROC) analysis, or intraclass correlation coefficient (ICC). Results: In differentiating endometrioid type from non-endometrioid type EC, all ADC histogram parameters were statistically significant (p < 0.05). In differentiating histological grades, 90th percentile ADC and ADCmax showed significantly higher values in tumor Grade III than in tumor Grade I-II (p < 0.05). In differentiating superficial myometrial invasion from deep myometrial invasion, all ADC histogram parameters were statistically significant (p < 0.05), except ADCmax. In differentiating non-high risk group from high risk group, ADCmean, 75th–90th percentile ADC, and ADCmax were statistically significant (p < 0.05). For predicting the high risk group, the area under the ROC curve of ADCmax was 0.628 and the highest among other histogram parameters. All histogram parameters revealed moderate to good inter-reader reliability (ICC = 0.581‒0.769). Conclusion: The ADC histogram analysis as reproducible tool may be useful for evaluating the pathological characteristics and risk stratification in patients with early-stage EC. Advances in knowledge: ADC histogram analysis may be useful for evaluating risk stratification in early-stage endometrial cancer patients.