Multiparametric Whole-Body MRI: A Game Changer in Metastatic Prostate Cancer

Abstract

Prostate cancer ranks among the most prevalent tumours globally. While early detection reduces the likelihood of metastasis, managing advanced cases poses challenges in diagnosis and treatment. Current international guidelines support the concurrent use of ⁹⁹Tc-Bone Scintigraphy and Contrast-Enhanced Chest and Abdomen CT for the staging of metastatic disease and response assessment. However, emerging evidence underscores the superiority of next-generation imaging techniques including PSMA-PET/CT and whole-body MRI (WB-MRI). This review explores the relevant scientific literature on the role of WB-MRI in metastatic prostate cancer. This multiparametric imaging technique, combining the high anatomical resolution of standard MRI sequences with functional sequences such as diffusion-weighted imaging (DWI) and bone marrow relative fat fraction (rFF%) has proved effective in comprehensive patient assessment, evaluating local disease, most of the nodal involvement, bone metastases and their complications, and detecting the increasing visceral metastases in prostate cancer. It does have the advantage of avoiding the injection of contrast medium/radionuclide administration, spares the patient the exposure to ionizing radiation, and lacks the confounder of FLARE described with nuclear medicine techniques. Up-to-date literature regarding the diagnostic capabilities of WB-MRI, though still limited compared to PSMA-PET/CT, strongly supports its widespread incorporation into standard clinical practice, alongside the latest nuclear medicine techniques.

Keywords: MRI; metastatic prostate cancer; oncological radiology; prostate cancer; radiology; whole-body MRI.

Figure 1

PRISMA flow diagram [12].

Figure 2

A 64 year-old patient who underwent radical prostatectomy for PC (Gleason score 4 + 4) presented with biochemical recurrence. A single focal bone metastasis located within the anterior aspect of a thoracic vertebral body (arrows) shows high DWI signal intensity (a), relatively low ADC values (mean ADC = 680 μm²/s) (b) and appears markedly hypointense on rFF% (c).

Figure 3

PC patient who had undergone radical prostatectomy in 2019 presented with significant biochemical relapse in 2022. WB-MRI showed supra- and infradiaphragmatic nodal disease (arrows), which can be easily identified through the assessment of DWI images (a) and measured on morphological axial T2 sequences (b). Three-dimensional MIP offers a panoramic visualization of the disease burden (c).

Figure 4

Prostate cancer patient (Gleason score 4 + 4) who underwent robot-assisted radical prostatectomy presented with biochemical recurrence. WB-MRI demonstrated a focal signal abnormality (arrows) consistent with local recurrence. (a) Axial b 800 DWIBS shows a focus of impeded diffusion in the right para-rectal space being confirmed in the ADC maps (b) and by the axial T2w images (c). Coronal maximum-intensity projection of b 800 DWIBS (e) offers a panoramic view. PSMA-PET/CT (d) could not detect the disease relapse; it was subsequently confirmed by choline-PET/CT.

Figure 5

Patient with bone metastatic CRPC who underwent baseline staging with standard techniques (BS and CT scan) and with WB-MRI prior to entering a clinical trial and after 8 weeks of treatment. Follow-up BS (b) suggested an increase in the disease burden compared to baseline (a). The same lesions showed signal characteristics consistent with highly cellular/active disease on baseline WB-MRI (c–e) (mean ADC = 833 μm²/s), while at follow-up scan (f–h), there was a significant increase in ADC values, in keeping with response to treatment (mean ADC = 1463 μm²/s; RAC = 1). BS appearances were interpreted as FLARE.