VALUE OF 3 TESLA MULTI-MODALITY DIRECTED MR GUIDED BIOPSY TO DETECT PROSTATE CANCER IN PATIENTS AFTER AT LEAST TWO PREVIOUS NEGATIVE BIOPSIES AND ELEVATED PSA

Abstract

(MRI), a novel platform that registers and fuses real-time US images with pre-procedure MRI was used. Feasibility and initial experience with MRUS fused targeted prostate biopsies with real time tracking performed outside MRI is described. METHODS: Under an IRB approved protocol patients with suspicion of prostate cancer (elevated PSA, history of prostate cancer) underwent a 3T endorectal-coil prostate MRI with T1, T2 weighted, dynamic contrast enhanced, diffusion weighted, and spectroscopy images. Lesions identified on MRI were scored for level of suspicion for cancer. A traditional 12-core US guided prostate biopsy was then performed. Subsequently, biopsies of MRI targeted lesions were performed using a custom probe and needle guide with spatial tracking within an electromagnetic field. Prostate US images were fused to MR images allowing for real-time US images and projected needle pathways on the corresponding MR location. RESULTS: 51 patients, mean age 62 (49-79) and mean PSA 8.1 (0.3 -46.9), underwent US-MR tracked fusion biopsy. 31 patients had prior prostate biopsy with 20 having known prostate cancer. 703 standard sextant biopsy cores and 352 tracked biopsy cores from 144 MRI targets were obtained. Core biopsies were analyzed by region (considered positive if at least 1 core at that region was positive). 18% (57/324) of the sextant regions and 25% (36/144) of the tracked regions were positive for cancer. 57% (29/51) of patients had positive biopsy with 19 (65%) on both sextant and tracked biopsy, 6 (21%) only positive on sextant biopsy and 4 (14%) on tracked biopsy only. Targets with increasing suspicion on MRI were more likely to be positive for cancer (see table). CONCLUSIONS: This phase I study demonstrates the feasibility and the clinical value (detecting 4 additional cases of cancer) of MR targeting of prostate lesions using real-time US images fused to preprocedure MRI and spatial tracking technology. Further studies are required to determine its role in cancer detection.