Will Multi-Parametric Magnetic Resonance Imaging be the Future Tool to Detect Clinically Significant Prostate Cancer?

Abstract

Multi-parametric magnetic resonance imaging is an emerging imaging modality for diagnosis, staging, characterization, and treatment planning of prostate cancer. In this report, we reviewed the literature for studies assessing the accuracy of multi-parametric magnetic resonance imaging in detecting clinically significant prostate cancer, and we critically examined the future role of this imaging tool in various clinical diagnostic settings. There is accumulating evidence suggesting a high accuracy of multi-parametric magnetic resonance imaging in ruling out clinically significant disease. Although definition for clinically significant disease widely varies, the negative predictive value is very high at up to 98%. Multi-parametric magnetic resonance imaging should, thus, be further evaluated for application in different clinical scenarios in which it is desirable to reduce the proportion of unnecessary prostate biopsies and to limit the detection of indolent disease, such as opportunistic screening, persistent prostate cancer suspicion in men with previous negative prostate biopsies, and eligibility for active surveillance. Continued improvement in standardization of technical parameters, functional sequences, and image reporting systems is a pre-requisite for a rapid and successful dissemination of this imaging modality.

Keywords: active surveillance; magnetic resonance imaging; prostate biopsy; prostate neoplasms; radical prostatectomy; screening.

Figure 1

Multi-parametric magnetic resonance imaging in a 65-year-old man referred for early detection of prostate cancer with an elevated serum PSA level (7 ng/ml) and a normal digital rectal examination. Magnetic resonance imaging consisted of conventional T2-weighted, diffusion-weighted, and dynamic contrast-enhanced sequences performed on a 3 T unit without endorectal coil. (A) An ovoidal hyperintense lesion (arrow) was observed on axial diffusion-weighted imaging at b-value 1000 s/mm² in left apical peripheral zone. (B) The lesion (arrow) corresponded to hypointense lesion on apparent diffusion coefficient map. (C) The lesion (arrow) also corresponded to axial T2-weighted image with low signal intensity, and to (D) focal enhanced lesion on axial dynamic contrast-enhanced imaging with a type 3 enhancement curve (washout) (E). The final Prostate Imaging Reporting and Data System score for this lesion was four. The presence of a clinically significant cancer was confirmed with a targeted biopsy, showing an 8-mm Gleason score 4 + 3 adenocarcinoma.