• Waterton, John
• Robinson, Simon
• Jamin, Yann
• Li, Jin
• Sinkus, Ralph
• Bamber, Jeffrey
• Ulloa, Jose
• Jk, Boult
• Cummings, C.

Abstract

<h4>Background</h4>Magnetic resonance elastography (MRE) is an emerging imaging technique that affords non-invasive quantitative assessment and visualization of tissue mechanical properties in vivo.<h4>Methods</h4>In this study, MRE was used to quantify (kPa) the absolute value of the complex shear modulus |G*|, elasticity Gd and viscosity Gl of SW620 human colorectal cancer xenografts before and 24 h after treatment with either 200 mg kg(-1) of the vascular disrupting agent ZD6126 (N-acetylcolchinol-O-phosphate) or vehicle control, and the data were compared with changes in water diffusivity measured by diffusion-weighted magnetic resonance imaging.<h4>Results</h4>A heterogeneous distribution of |G*|, Gd and Gl was observed pre-treatment with an intertumoral coefficient of variation of 13% for |G*|. There were no significant changes in the vehicle-treated cohort. In contrast, ZD6126 induced a significant decrease in the tumour-averaged |G*| (P<0.01), Gd (P<0.01) and Gl (P<0.05), and this was associated with histologically confirmed central necrosis. This reduction in tumour viscoelasticity occurred at a time when no significant change in tumour apparent diffusion coefficient (ADC) was observed.<h4>Conclusions</h4>These data demonstrate that MRE can provide early imaging biomarkers for treatment-induced tumour necrosis.

Topics

• impedance spectroscopy
• viscosity
• viscoelasticity
• elasticity
• diffusivity