Multiparametric MRI: Local Staging of Prostate Cancer

Abstract

To highlight the recent evidence about the use of mp-MRI in the local staging of prostate cancer, enhancing the potential benefits compared to the known and more invasive canonical staging methods. Multiparametric magnetic resonance (mp-MRI) plays a key role not only in diagnosis, but also in local staging of prostate cancer, as it can assess with high accuracy the extracapsular extension of the tumor, invasion of seminal vesicles, the involvement of lymph nodes and the presence of possible bone metastases. Prostate cancer is currently the most common male cancer in Europe and it is associated with a high mortality rate, which is why it is necessary to make an early and accurate diagnosis. Firstly, it is important to distinguish between a disease confined to the gland and a disease with a loco regional or remote extension, since neoplastic staging is the starting point for risk stratification, prognosis and therapeutic planning. According to the PI-RADS guidelines v 2.1 the main mp-MRI sequences necessary to obtain a complete and accurate resonance imaging are the T2-weighted sequences (T2WI), which represent the pivotal morphological sequences for local staging, together with the diffusion-weighted imaging (DWI) and dynamic sequences acquired after intravenous contrast medium administration (DCE). However, due to some limitations, mp-MRI does not have the same diagnostic power in the evaluation of lymph nodes, for which the gold standard remains the extended pelvic nodal dissection (ePLND), nor in the detection of distant metastases. For this last aspect, the next generation imaging foresees the use of whole-body MRI (WB-MRI), especially for the high accuracy in the early detection of local and remote bone metastases.