Quantitative Diagnosis for Liver and Heart Desease Using Ultrasonic RF Images

本研究的目的是探讨组织的生理变化和回波信号信息与疾病的关系，发展心脏和肝脏疾病的定量诊断方法。我们测量了心力衰竭、肝硬变和慢性肝炎组织的声学特性。正常组织和病变组织的声学特性不同，纤维结构具有声速和衰减分布的特征。利用数字化超声诊断仪对射频回波信号的幅度分布进行了分析。纤维组织回波信号幅值的概率密度函数不同于瑞利分布，而正常组织回波信号幅值的概率密度函数近似符合瑞利分布。证实了随着肝病分期从正常到肝硬变，信号幅值概率密度逐渐从瑞利分布变化。然后尝试利用回波信号中非瑞利分量的统计处理技术来提取纤维组织的三维结构。提取的信息作为非瑞利分量随着疾病的进展而增加。提取的三维结构似乎与纤维组织结构相对应，发现射频回波信息定量地反映了组织特征的变化。该技术可用于肝脏和心脏疾病的定量诊断。

The purpose of this study is to examine the relationship between physical change and echo signal information of tissues with the disease and develop the quantitative diagnosis method of heart and liver diseases. We measured the acoustic characteristics of tissues of heart failure, liver cirrhosis and chronic hepatitis. The acoustic characteristics were different in normal tissue and diseased tissue, and the fiber structure has the characteristic features of sound velocity and attenuation distribution. The analysis of amplitude distribution of RF echo signal was carried out using the digital ultrasonic diagnostic equipment. The probability density functions of echo signal amplitude from the fibrotic tissue are different from the Rayleigh distribution, while the probability density functions of echo signal amplitude from the normal tissue agree approximately with the Rayleigh distribution. It was confirmed that signal amplitude probability density gradually changed from the Rayleigh distribution, as the stage of liver disease progress from the normal to liver cirrhosis. Then we tried to the extract of three-dimensional structure of fibrotic tissues using the statistically processing technique for non-Rayleigh component in echo signal. The extracted information as a non-Rayleigh component increases with the progress of the disease. It seems that the extracted three-dimensional structure corresponds to the fibrous tissues structure.It is found that the RF echo information reflects the change of the tissue characteristics quantitatively. The proposed technique is valid for the quantitative diagnosis of liver and heart diseases.