Magnetic resonance-ultrasound fusion prostate biopsy in the diagnosis of prostate cancer

Abstract

The advent of multiparametric magnetic resonance imaging (MRI) has ushered in a new era for urologists who perform prostate needle biopsies. The fusion of MRI with transrectal ultrasound (US) allows the direct targeting of suspicious lesions, which has been shown to improve the performance of conventional random biopsy techniques by increasing detection of clinically relevant disease while also decreasing detection of low-risk cancer. However, as with any new technology, many questions regarding effectiveness, reproducibility, and generalizability still remain. In this review, we (1) provide a summary of the various sequences that comprise a MRI of the prostate; (2) evaluate the 3 different ways of incorporating MRI into targeted biopsies of the prostate including in-bore MRI-guided biopsy, cognitive fusion, and device-mediated fusion; (3) review the sensitivity of MR-US fusion in the detection of clinically significant and clinically insignificant disease; and (4) review the barriers to the widespread implementation of MR-US fusion into everyday practice. Whereas other articles in this issue of Urologic Oncology Seminars will discuss other aspects of MRI in the management of prostate cancer, the purpose of this article is to provide an overview of MR-US fusion biopsies in the diagnosis of prostate cancer.

Keywords: Fusion; Magnetic Resonance Imaging; Prostate Biopsy; Prostate Cancer; Ultrasound.

Figure 1

66-year-old male with history of elevated PSA and BPH, status post multiple negative TRUS prostate biopsies and PSA level of 7.46. A 3T prostate MRI without endorectal coil was performed for the purpose of MR-US fusion biopsy. Images show a mildly T2 hypointense lesion in the apex just anterior to the urethra (arrow) which demonstrates markedly increased signal on diffusion weighted image (top right), corresponding darkness on ADC map signifying decreased ADC value (bottom right) and early enhancement on DCE images (asterisk). MR-US fusion biopsied confirmed a Gleason 4+3 lesion.