Modeling of Shear Wave Propagation Near Inflamed Lung with Fluid Accumulation

Shear wave elastography is a technique used to visualize the propagation characteristics of shear waves in human tissues. Studies have been conducted on its application in the diagnosis of inflamed lungs. However, ultrasound does not penetrate the lungs because of air, making it difficult to accurately measure shear waves in the lungs. In this study, we established a model of shear wave propagation in the chest wall near an inflamed lung with fluid accumulation. We hypothesized that in the inflamed lung model, the attenuation of the shear wave propagating in the chest wall along the lung surface is large due to energy leakage into the fluid-filled lung. Finite-difference time-domain simulations and animal experiments using goats were conducted. In both the simulation and animal experiments, stronger energy leakage was observed in the inflamed lung, and the attenuation coefficients for the inflamed lung models were larger than those for the normal lung models. From the results, we confirmed that the shear wave propagation model could be used to characterize inflamed lungs.