The intensity of backscattered ultrasound signal from heart tissue is known to be related to the angle between cardiac fibers and the insonification direction. In this work, we use optical ray tracing, fast convolutions with the system point spread function, and an empirically derived relationship between backscatter intensity and fiber orientation to simulate plane wave echocardiography on the GPU. First, we simulate grayscale images of a rotating fiber phantom, and validate that the angle-to-backscatter relationship is accurately reflected by the simulated radiofrequency data. Second, we use our method to simulate view-dependent echocardiography images of human heart tissue from diffusion tensor magnetic resonance imaging (DT-MRI) data. Simulated backscatter intensity measurements show excellent agreement with the underlying angle-to-backscatter relationship, and echocardiography images exhibit view-dependent speckle with a realistic appearance. Our GPU-based simulation method is fast and generates biologically realistic images, making it particularly useful for fiber orientation quantification and many other ultrasound imaging studies.
|