Computational aspects of Young's modulus reconstruction from ultrasonic freehand scanning

In this paper, we report a method for absolute Young's modulus reconstruction under freehand scanning. The absolute modulus, an intrinsic tissue property, can be used to quantitatively monitor pathological evolution of certain diseases and to evaluate therapeutic treatments. This method could iteratively assess the absolute tissue modulus distribution by simultaneously measuring the surface pressure and tissue deformation. This method could also be used to obtain pressure-sensitive tissue elasticity through a sequence of phase sensitive (either radiofrequency or quadrature) echo signals to study tissue nonlinearity. Since the proposed method uses clinical equipment and procedures that are similar to the standard clinical examinations, this approach is likely to gain significant clinical impact if successful. Numerical simulations and a phantom experiment are reported here as preliminary studies with emphasis on computational aspects. The results show that the modulus distribution can be accurately reconstructed, though work in hardware and algorithm development needs to continue prior to clinical trials.