| Summary: | 碩士 === 國立臺灣大學 === 生醫電子與資訊學研究所 === 101 === High frequency ultrasound has been widely used to investigate various mice models of diseases and to evaluate effect and safety of new health care technologies in preclinical studies. Recently, shear wave elasticity imaging has become an important imaging technique because it can provide quantitative results in real time to assist clinical diagnosis. However, most applications of elasticity imaging are currently only available on clinical array systems but not preclinical single element systems. Therefore, it is the purpose of this research is to design, implement and evaluate shear wave elasticity imaging on single element high frequency ultrasound system. High frequency ultrasound provides high spatial resolution which is not only suitable for observing microstructures but also better suited for the detection of smaller displacement resulted from shear wave propagation. Compared with conventional elasticity imaging systems using arrays, the main technical challenge of our system is the generation and detection of shear wave as arrays are not available for ultrafast imaging. Hence, a mechanical scanning system with confocal transducer design (one transducer for generation of shear wave and the other for detection of displacement) was proposed and implemented. By auto-correlation, we can calculate the shear wave displacement, and subsequently estimate the shear modulus using either the time-of-flight method or the k-space method. Performance of the proposed system was verified with both phantom experiments and in vivo mouse imaging with a liver disease model. It is concluded that the proposed system can be a new and effective tool in preclinical research.
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