Investigating the heterogeneity of viscoelastic properties in prostate cancer using MR elastography at 9.4T in fresh prostatectomy specimens

Magn Reson Imaging. 2022 Apr:87:113-118. doi: 10.1016/j.mri.2022.01.005. Epub 2022 Jan 7.

Abstract

Purpose: To quantify the heterogeneity of viscoelastic tissue properties in prostatectomy specimens from men with prostate cancer (PC) using MR elastography (MRE) with histopathology as reference.

Methods: Twelve fresh prostatectomy specimens were examined in a preclinical 9.4T MRI scanner. Maps of the complex shear modulus (|G*| in kPa) with its real and imaginary part (G' and G" in kPa) were calculated at 500 Hz. Prostates were divided into 12 segments for segment-wise measurement of viscoelastic properties and histopathology. Coefficients of variation (CVs in %) were calculated for quantification of heterogeneity.

Results: Group-averaged values of cancerous vs. benign segments were significantly increased: |G*| of 12.13 kPa vs. 6.14 kPa, G' of 10.84 kPa vs. 5.44 kPa and G" of 5.45 kPa vs. 2.92 kPa, all p < 0.001. In contrast, CVs were significantly increased for benign segments: 23.59% vs. 26.32% (p = 0.014) for |G*|, 27.05% vs. 37.84% (p < 0.003) for G', and 36.51% vs. 50.37% (p = 0.008) for G".

Discussion: PC is characterized by a stiff yet homogeneous biomechanical signature, which may be due to the unique nondestructive growth pattern of PC with intervening stroma, providing a rigid scaffold in the affected area. In turn, increased heterogeneity in benign prostate segments may be attributable to the presence of different prostate zones with involvement by specific nonmalignant pathology.

Keywords: Heterogeneity; MR elastography; Prostate cancer; Prostatectomy specimens; Viscoelastic tissue properties; Whole-mount pathology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Elasticity Imaging Techniques*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Prostate / diagnostic imaging
  • Prostate / pathology
  • Prostate / surgery
  • Prostatectomy
  • Prostatic Neoplasms* / diagnostic imaging
  • Prostatic Neoplasms* / pathology
  • Prostatic Neoplasms* / surgery