Tomoelastography Based on Multifrequency MR Elastography for Prostate Cancer Detection: Comparison with Multiparametric MRI

Background: Multiparametric MRI is used for depiction of prostate cancer (PCa) but without consideration of the mechanical alteration of prostatic tissue by cancer. Purpose: To investigate the diagnostic performance of stiffness and fluidity quantified with tomoelastography, a multifrequency MR elastography technique, for depiction of PCa compared with multiparametric MRI with Prostate Imaging Reporting and Data System (PI-RADS) version 2.1. Materials and Methods: Prospective participants suspected to have PCa and healthy controls (HCs) underwent multiparametric MRIand tomoelastography between March 2019 and July 2020. Tomoelastography maps of shear-wave speed (c) and loss angle (phi) quantified stiffness and fluidity, respectively, for PCa and benign prostatic disease and for the peripheral and transition zones in HCs. Differences between entities and regions were analyzed by using analysis of variance or Kruskal-Wallis test. Diagnostic performance was assessed with area under the receiver operating characteristic curve (AUC) analysis. Results: There were 73 participants with PCa (mean age, 72 years +/- 7 [standard deviation]), 82 with benign prostatic disease (66 years +/- 7), and 53 HCs (41 years +/- 14). Mean +/- standard deviation of c and w were higher in PCa (3.4 m/sec +/- 0.6 and 1.3 radian +/- 0.2, respectively) than in benign prostatic disease (2.6 m/sec +/- 0.3 and 1.0 radian +/- 0.2, respectively; P<.001) and age-matched HCs (2.2 m/sec +/- 0.1 and 0.8 radian +/- 0.1, respectively; P<.001). Incorporating c and phi (AUC, 0.95; 95% CI: 0.92, 0.98) improved the diagnostic performance of PI-RADS version 2.1 (AUC, 0.85; 95% CI: 0.80, 0.91; P<.001). Multiparametric MRI combined with c and phi enabled detection of PCa with 95% (78 of 82 non-PCa) specificity, which was significantly higher than with use of multiparametric MRI alone (77% [63 of 82 non-PCa]; P<.001). In regional analysis, c combined with phi enabled differentiation of transition zone PCa from benign prostatic hyperplasia (AUC, 0.91; 95% CI: 0.83, 0.98) and peripheral zone PCa from chronic prostatitis (AUC, 0.94; 95% CI: 0.88, 1.00). Conclusion: Use of tomoelastography-quantified stiffness and fluidity improved the diagnostic performance of multiparametric MRI with Prostate Imaging Reporting and Data System version 2.1 in detecting cancer in both the peripheral and transition zones. (C) RSNA, 2021

Automated summary

The study investigated the diagnostic performance of stiffness and fluidity quantified with tomoelastography compared to multiparametric MRI in depicting prostate cancer. The results showed that combining stiffness and fluidity improved the diagnostic performance of detecting PCa, demonstrating higher specificity and better differentiation in both the peripheral and transition zones.