Techniques and Outcomes of MRI-TRUS Fusion Prostate Biopsy

Abstract

Purpose of review: The goal of this study is to review recent findings and evaluate the utility of MRI transrectal ultrasound fusion biopsy (FBx) techniques and discuss future directions.

Recent findings: FBx detects significantly higher rates of clinically significant prostate cancer (csPCa) than ultrasound-guided systematic prostate biopsy (SBx), particularly in repeat biopsy settings. FBx has also been shown to detect significantly lower rates of clinically insignificant prostate cancer. In addition, a dedicated prostate MRI can assist in more accurately predicting the Gleason score and provide further information regarding the index cancer location, prostate volume, and clinical stage. The ability to accurately evaluate specific lesions is vital to both focal therapy and active surveillance, for treatment selection, planning, and adequate follow-up. FBx has been demonstrated in multiple high-quality studies to have improved performance in diagnosis of csPCa compared to SBx. The combination of FBx with novel technologies including radiomics, prostate-specific membrane antigen positron emission tomography (PSMA PET), and high-resolution micro-ultrasound may have the potential to further enhance this performance.

Keywords: Fusion biopsy; Image registration; Magnetic resonance imaging; Prostate cancer; Systematic biopsy; Ultrasonography.

Fig. 1

Techniques and strategies for prostate biopsy. (I) Coronal view of 3D-TRUS-guided transrectal prostate biopsy (blue cores); (II) coronal view of 3D-TRUS fusion-guided second-look surveillance prostate biopsy (green cores). Note that green cores on second-look biopsy overlay the blue cores (positive for cancer) in the right mid-lateral and medial regions, while other cores are in areas un-sampled on initial biopsy. (III) Coronal and (IV) left sagittal view of 3D mapping of a restaging MRI-TRUS fusion transrectal prostate biopsy on a candidate for focal therapy. Note that, in the left lobe, the cores are taken in the center and around the lesion, medially next to the urethra, as well as in the extreme proximal (towards the bladder) and distal (towards the apex) margins of the prostate. This strategy allows for 3D mapping of the prostate and any tumors; (V and VI) coronal view of surveillance biopsy after left hemi-gland cryoablation of the prostate in the same patient as III and IV. Although surveillance MRI was negative, 3D mapping of the prostate and tumors the cancer allowed for second-look tracking. (VII) Transverse and (VIII) left sagittal view of systematic and target transperineal MRI-TRUS fusion prostate biopsy performed under local anesthesia. A, apex; B, base; R, right; L, left; Ant, anterior; P, posterior; 3D, three-dimensional; TRUS, transrectal ultrasound; MRI, magnetic resonance imaging