Automated Real-time Needle-Guide Tracking for Fast 3-T MR-guided Transrectal Prostate Biopsy: A Feasibility Study

Purpose: To assess the feasibility of automatic needle-guide tracking by using a real-time phase-only cross correlation (POCC) algorithm-based sequence for transrectal 3-T inbore magnetic resonance (MR)-guided prostate biopsies. Materials and Methods: This study was approved by the ethics review board, and written informed consent was obtained from all patients. Eleven patients with a prostate-specific antigen level of at least 4 ng/mL (4 mu g/L) and at least one transrectal ultrasonography-guided biopsy session with negative findings were enrolled. Regions suspicious for cancer were identified on 3-T multiparametric MR images. During a subsequent MR-guided biopsy, the regions suspicious for cancer were reidentified and targeted by using the POCC-based tracking sequence. Besides testing a general technical feasibility of the biopsy procedure by using the POCC-based tracking sequence, the procedure times were measured, and a pathologic analysis of the biopsy cores was performed. Results: Thirty-eight core samples were obtained from 25 regions suspicious for cancer. It was technically feasible to perform the POCC-based biopsies in all regions suspicious for cancer in each patient, with adequate biopsy samples obtained with each biopsy attempt. The median size of the region suspicious for cancer was 8 mm (range, 4-13 mm). In each region suspicious for cancer (median number per patient, two; range, 1-4), a median of one core sample per region was obtained (range, 1-3). The median time for guidance per target was 1.5 minutes (range, 0.7-5 minutes). Nineteen of 38 core biopsy samples contained cancer. Conclusion: This study shows that it is feasible to perform transrectal 3-T MR-guided biopsies by using a POCC algorithm-based real-time tracking sequence. (C) RSNA, 2014