Elastic Property Monitoring by Radiation Force Impulse and Phase Contrast Imaging

Abstract

In tissue engineering, one promising methodology is the scaffold based approach, where an artificial construct is seeded with cells, which then proceed to organize and proliferate into new tissue. The scaffold then biodegrades, leaving behind the newly formed tissue that originally developed in the scaffold’s pores. The degradation behavior of the scaffold is critical to its performance during the treatment period, since the decline in scaffold mechanical properties influences the loading of the tissue developing in the scaffold pores, which is known to have an effect on cell behavior. To monitor the scaffold’s mechanical properties, soft scaffolds are deformed by the acoustic radiation force generated by an ultrasound source. Measuring the deflection the scaffold experiences from this ultrasound based radiation force is challenging, since the scaffold is surrounded by the living environment. In this paper, an in-vitro methodology is presented, proceeding from scaffold fabrication, scaffold imaging, image analysis, mathematical equations, and finally model implementation. The innovation comes from the author’s use of in-line phase contrast x-ray imaging at 20 KeV to characterize tissue scaffold deformation from ultrasound radiation forces, and the measured deformation is then compared with predictions given by the forward solution of a mathematical model.