Simulation of HMIFU (Harmonic Motion Imaging for Focused Ultrasound) with in-vitro validation

Harmonic Motion Imaging (HMI) is a technique capable of imaging tissue mechanical properties during acoustic radiation force application. Recently, HMIFU has been shown capable for high-intensity focused ultrasound (HIFU) therapy and monitoring. Here, a theoretical analysis of the Harmonic Motion Imaging for Focused Ultrasound (HMIFU) system is performed using a 2D nonlinear wave propagation model combined with a finite-element (FE) framework and its reliability in lesion localization and size quantification is tested in both simulations and in-vitro experiments. Good agreement in both lesion size (2.86, 5.93 and 17.5 mm², for 5-, 10-, and 20-s ablation cases, respectively) and location (4.8 cm to 5.2 cm, 4.6 cm to 5 cm, and 4.4 cm to 5.1 cm, in the 5-, 10- and 20-s ablation cases, respectively) were found between the predicted lesion maps and the HMIFU images in both simulations and in vitro. Along with preliminary Finite-element (FE) results, the presented work confirms the reliability of the HMIFU system for lesion detection, localization and quantification.