V1267: Targeted Biopsy with MRI-Ultrasound Fusion

V1267: Targeted Biopsy with MRI-Ultrasound Fusion


Introduction and Objectives
Targeted biopsy of prostate lesions identified on magnetic resonance imaging (MRI) may improve detection of clinically significant prostate cancer (CaP). We previously described the initial clinical use of a 3D biopsy tracking and targeting device that fuses MRI with real-time ultrasound (US), permitting targeted prostate biopsy (Artemis; Eigen, Grass Valley, CA; Urol. Oncol. 29: 334, 2011). We now provide a detailed video account of the MR-US fusion targeted biopsy process.

Subjects in this IRB-approved study were in active surveillance (N=197), had prior negative biopsies but persistently elevated PSA (N=105), or underwent first time biopsy (N=84) from 3/2010 to 8/2012. Prior to biopsy, each man had a multiparametric MRI at 3-Tesla, combining T2-weighted imaging (T2WI), dynamic contrast enhancement (DCE), and diffusion-weighted imaging (DWI). A pelvic phased-array coil was used. Lesions (targets) on MRI were outlined in 3D and assigned a cancer suspicion level (image grade 1 to 5) by a uro-radiologist. At biopsy, the Artemis device was attached to a conventional ultrasound probe and a scan of the prostate was performed. The stored MRI was fused with real-time US in the Artemis device, generating a 3D prostate model on-the-fly. Working from the 3D model, transrectal biopsy of target lesions at 3 mm intervals and 12 systematic biopsies were performed under local anesthesia in the clinic.

386 subjects (mean age 65) underwent 443 fusion biopsy sessions. At biopsy, median PSA was 5.3 ng/ml and prostate volume was 44 cc. Mean time from probe insertion to last biopsy was ~20 minutes. CaP was found in 211 of 386 men (55%). 108 cancers (51%) were Gleason ≥7. Targeted biopsy findings correlated with level of suspicion on MRI. 32 of 35 (91%) men with an image grade 5 target had CaP on biopsy. Of these, 25 (78%) were Gleason ≥7. In the patients with prior negative biopsies, CaP was diagnosed in 36 of 105 (34%). Of these, 22 (61%) were Gleason ≥7. In the active surveillance group, 138 of 197 (70%) had CaP on biopsy. In both groups, the targeted cores increased the detection of clinically significant cancers over those found on systematic biopsy alone.

Prostate lesions identified on MRI can be accurately targeted using MR-US fusion biopsy in a clinic setting. This process enables detection of significant tumors missed on blind biopsy.

Funding: Beckman Coulter Foundation, Steven C. Gordon Family Foundation, the Jean Perkins Foundation, and NIH/NCI 1R01CA158627-01