FAMUS II: A Fast and Mechanistic Ultrasound Simulator Using an Impulse Response Approach.

Real-time simulation of ultrasound images is increasingly important for providing a means of presenting a wide variety of clinical images for the training of ultrasound specialists and technologists. In order to realistically represent the visual effects caused by changes to the transducer position or its focal properties, very rapid transducer field response calculations are needed, typically on the order of a fraction of a second. Currently available methods are severely limited in this regard. Based on the impulse response, a point source/receiver method for accurately calculating the fields produced by ultrasound transducer arrays is proposed and illustrated with realistic B-mode and Doppler spectral display simulations. The results of this method (FAMUS II), which accounts for the attenuation frequency dependence of the propagating medium, are compared with those obtained with Field II both in terms of quality and computational speed. From a clinical simulation perspective, the qualitative differences are small. Because the method is inherently parallelizable, significant gains in computational speed can be achieved. For example, in B-mode imaging using an eight-core CPU, FAMUS II is shown to be more than two orders of magnitude faster than that achieved by Field II. As a result, we believe that this new method represents a significant step toward achieving real-time performance.