Shear Wave Elastography Can Differentiate between Radiation-Responsive and Non-responsive Pancreatic Tumors: An ex Vivo Study with Murine Models

Ultrasound Med Biol. 2020 Feb;46(2):393-404. doi: 10.1016/j.ultrasmedbio.2019.10.005. Epub 2019 Nov 11.

Abstract

Neither contrast-enhanced computed tomography nor magnetic resonance imaging can monitor changes in the pancreatic ductal adenocarcinoma microenvironment during therapy. We hypothesized that shear wave elastography could overcome this limitation. To test this hypothesis, we measured the shear modulus of two groups of murine pancreatic tumors (KCKO, n = 30; PAN02, n = 30) treated with stereotactic body radiation therapy (SBRT). The mean shear modulus of KCKO tumors was 7.651 kPa higher than that of PAN02 tumors (p < 0.001). SBRT reduced the shear modulus in KCKO tumors by 8.914 kPa (p < 0.001). No significant difference in the shear modulus of SBRT-treated PAN02 tumors was observed. Additionally, necrotic and collagen densities were reduced only in the SBRT-treated KCKO tumors. Shear modulus was dependent on collagen distribution and histological texture parameters (i.e., entropy and fractional dimension). Shear wave elastography imaging differentiates between SBRT-responsive (KCKO) and non-responsive (PAN02) tumors.

Keywords: Pancreatic ductal adenocarcinoma; Shear modulus; Stereotactic body radiation therapy; Tumor microenvironment.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Carcinoma, Pancreatic Ductal / diagnostic imaging*
  • Carcinoma, Pancreatic Ductal / radiotherapy*
  • Diagnosis, Differential
  • Disease Models, Animal
  • Elasticity Imaging Techniques*
  • Female
  • Mice
  • Mice, Inbred C57BL
  • Pancreatic Neoplasms / diagnostic imaging*
  • Pancreatic Neoplasms / radiotherapy*
  • Treatment Outcome