Application of Spatial Autocorrelation in Experimental Time-Harmonic Elastography

Elastography is an imaging technique in which the elastic properties of tissues are estimated and displayed. These are then used in, for example, the diagnosis and staging of various diseases. In the current paper, we describe our contribution to the Algorithms for Mapping Elastic Modulus (a-MEM) Challenge 2024 which is submitted to the category of propagating shear waves from harmonic (continuous) vibration sources. A method that employs directional filters followed by spatial autocorrelation was applied to the data shared by the challenge organizers. In the applied method, directional filters oriented along 12 different angles were employed to decompose the displacement field into shear waves traveling in different directions. A shear-wave speed estimation method based on spatial autocorrelation was applied to filtered complex-valued images. Final shear-wave speed estimates are generated by averaging all shear-wave speed estimates from different directional filter angles and transmission angles.The results showed a good correlation between the given and estimated inclusion coordinates and the method showed a potential that warrants further assessment with in vivo experiments.