MR-ARFI-based method for quantitative measurement of tissue elasticity: application to monitoring of HIFU therapy.

MR-ARFI-based method for quantitative measurement of tissue elasticity: application to monitoring of HIFU therapy. Phys Med Biol. 2018 Apr 10;: Authors: Vappou J, Bour P, Marquet F, Ozenne V, Quesson BAJ Abstract Monitoring thermal therapies thanks to medical imaging is essential in order to ensure that they are safe, efficient and reliable. In this paper, we propose a new approach, halfway between MR Acoustic Radiation Force Imaging (MR-ARFI) and MR Elastography (MRE), allowing for quantitative measurement of tissue's elastic modulus in a highly localized manner. It relies on the simulation of the MR-ARFI profile, which depends on tissue biomechanical properties, and on the identification of tissue elasticity through the fitting of the experimental displacement images measured using rapid MR-ARFI. Such method was specifically developed for the monitoring of MR-guided High Intensity Focused Ultrasound (MRgHIFU) therapy. Elasticity changes were followed during HIFU ablations (N=6) performed ex vivo in porcine muscle samples, and were compared to temperature changes measured by MR-Thermometry. Shear modulus was found to increase consistently and steadily a few seconds after the heating started, and such changes were found to be irreversible. The shear modulus was found to increase from 1.49±0.48 kPa (before ablation) to 3.69±0.93 kPa (after ablation and cooling). Thanks to its ability to perform quantitative elasticity measurements i...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research