Real-time Contrast-enhanced Transrectal US-guided Prostate Biopsy: Diagnostic Accuracy in Men with Previously Negative Biopsy Results and Positive MR Imaging Findings

Purpose: To retrospectively evaluate diagnostic accuracy of real-time contrast material-enhanced (CE) ultrasonography (US) transrectal US-guided biopsies in patients with persistently elevated prostate-specific antigen (PSA) levels, previous negative systematic transrectal US-guided biopsy results, and positive prostate multiparametric magnetic resonance (MR) findings. Materials and Methods: Institutional review board approval was obtained for this retrospective study. Informed consent was waived. From 2007 to 2011, 178 patients with increased PSA levels (mean, 10.7 ng/mL [10.7 mg/L]), previous negative findings of random biopsies, and targets depicted at multiparametric MR imaging underwent transrectal US-guided prostate biopsies after injection of sulfur hexafluoride microbubbles. CE US-targeted biopsies were performed systematically in cancer-suggestive regions, followed by random acquisition of 12 nontargeted cores in all other regions. Diagnostic accuracy of CE US-targeted biopsies was measured with sensitivity, specificity, and positive and negative predictive values. Fisher exact and Mann-Whitney U tests were used to compare subgroups of patients. Potential predictive variables were examined with a logistic regression model. Results: CE US findings were positive in a first group of 158 patients and negative in a second group of 20 patients. Prostate carcinoma (PCa) was detected in 75 patients in the first group (47.5%) and in eight of the second group (40.0%). Overall cancer detection rate was 46.6% (83 of 178). In the first group, PCa was detected with targeted biopsies alone in 18 patients (24%), with nontargeted biopsies alone in 23 (30.7%), and with both in 34 (45.3%). Mean number of CE US-targeted cores per cancer-suggestive region was 2.2. CE US-targeted biopsies had a positive overall detection rate of 30.9%, while it was 6.9% for 12-core nontargeted biopsies (P < .001). PSA level and Gleason score were associated with positivity of CE US-targeted biopsies (P = .031 and P = .015, respectively). Conclusion: Real-time CE US-targeted transrectal US biopsy offers excellent sensitivity for PCa detection in men with previous negative biopsy results and positive findings at multiparametric MR imaging. It may be combined with conventional random biopsies to increase specificity. (C) RSNA, 2013