Diagnostic ultrasound is a non-invasive image modality commonly used to diagnose multiple diseases. Sonographers and physicians have to devote a substantial amount of time learning how the combination of the various parameters of the ultrasound system affects the resulting ultrasound information among its different modalities. The primary objective of this thesis is to create a mechanistic ultrasound simulation method that could achieve near real-time performance to teach and train sonographers and physicians. A major bottleneck for achieving real-time performance with available tools was the transducer field simulation method that uses the impulse response technique. To address this problem a new simulation approach was developed. This project was realized in a three-phase approach, specifically to simulate spectral Doppler. In first place, it was shown that is possible to mechanistically simulate the sample volume power distribution using a novel method based on an array of point sources to represent the transducer geometry. Secondly, by comparison with the Field II results, it was demonstrated that the time-domain signal could be closely reproduced using point sources. Finally, by treating the array of point sources as point receivers, the received signal was compared with the results from Field II, and again, good agreement was achieved. Simulation results were compared against the standard simulation method for a number of examples involving steady and pulsatile flow, for which the spectrograms were compared against Field II. Also presented are preliminary results obtained using the point source approach to simulate B-mode images. As well, methods are described for generating Doppler spectrograms from the results of computation fluid dynamics velocity fields obtained in realistic arterial geometrical models. It is pointed out that the successful simulation of the time domain signal opens the possibility for real-time simulation of other ultrasound modes.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/33899 |
| Date | 06 December 2012 |
| Creators | Aguilar Beltran, Luis Alberto |
| Contributors | Steinman, David, Cobbold, Richard |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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