Feasibility of multifrequency MR elastography of the seminal vesicles in healthy men, benign prostatic hyperplasia, and prostate cancer.

[OBJECTIVE] The seminal vesicles (SVs) are important for reproductive health and prostate cancer (PCa) staging. Nevertheless, their biophysical properties remain largely unexplored. This secondary analysis investigates the feasibility and potential of multifrequency magnetic resonance elastography (MRE) in characterizing viscoelastic properties of the SVs across healthy subjects, men with benign prostatic hyperplasia (BPH), and patients with PCa.

[MATERIALS AND METHODS] Sixty-two male participants (24 healthy, 25 BPH, 13 PCa) underwent pelvic MRE and diffusion-weighted imaging (DWI). We assessed shear wave speed (SWS), phase angle φ, apparent diffusion coefficient (ADC) and normalized ADC (nADC). Statistical comparisons across groups were performed using Kruskal-Wallis and Dunn tests. Test-retest and bilateral agreement were analyzed using intraclass correlation coefficients (ICCs).

[RESULTS] MRE of the SVs was technically feasible with excellent reproducibility, particularly for φ (ICC = 0.989), which was also significantly higher in BPH (p = 0.022) and PCa patients (p = 0.019), compared to healthy controls, showing elevated tissue fluidity in disease. While SWS and ADC did not differ significantly across groups, nADC was significantly reduced in BPH and PCa patients compared to healthy subjects (p < 0.001). No significant differences were detected between PCa patients with and without seminal vesicle invasion.

[CONCLUSION] Multifrequency MRE of the SVs is feasible and highly reproducible, allowing reliable assessment of their viscoelastic properties. Tissue fluidity may serve as a sensitive imaging biomarker. Further studies are warranted to explore the role of SV fluidity in disease progression and diagnosis.

[RELEVANCE STATEMENT] Multifrequency MRE enables the in vivo viscoelastic characterization of the SVs. It demonstrates disease-related increases in tissue fluidity in BPH and PCa. These findings showcase φ as a promising imaging biomarker for pathologies of the SVs and the prostate.

[KEY POINTS] Multifrequency MRE provides an in vivo assessment of SVs biomechanics across healthy men and patients with BPH or PCa. Across all mechanical parameters, tissue fluidity (φ) demonstrates the highest sensitivity to pathological changes. The excellent reproducibility of φ underscores its potential use in future diagnostics targeting prostate and SVs disease.