| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 104 === Conventionally, ultrasound diagnosis of nonalcoholic fatty liver disease (NAFLD) relies on the physician’s judgement on texture and brightness of liver tissue in B-mode imaging. In this study, quantitative acoustic parameters such as statistical characteristics of signal envelope (ASQ), integrated backscattering coefficient (IB) and attenuation coefficient (ATN) are utilized to differentiate the NAFLD liver from the normal liver. For attenuation coefficient, the estimation accuracy significantly changes with the ROI spacing and the ROI position relative to the transmit focal zone. Our results indicate that a pre-focus setting can reduce the bias of measured attenuation coefficient to 4.82% and 2.35%, respectively in phantom experiment and simulation. A larger ROI spacing can further improve the accuracy of attenuation estimation. Animal experiments are performed by feeding mice with normal diet (NL group) and high-fat diet (HF group) for three months and then acquiring ultrasound images of mice at 20 MHz for estimation of acoustic parameters. Compared to the NL group, the HF group exhibits higher IB and higher ATN together with lower ASQ. The difference of IB, ATN and ASQ between the NL and HF groups is all statistically significant (p < 0.05). Therefore, integration of these acoustic parameters may provide a reliable index for quantitative NAFLD diagnosis.
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