Zhang D, Gong X, Ye S
Institute of Acoustics, Nanjing University, People's Republic of China.
J Acoust Soc Am. 1996 Apr;99(4 Pt 1):2397-402. doi: 10.1121/1.415427.
The acoustic nonlinearity parameter B/A is a new parameter in ultrasound tissue characterization. In this paper, on the basis of a theoretical analysis of finite amplitude ultrasonic wave propagation in fluidlike media, an experimental system for nonlinearity parameter tomography is developed. Using this system, the amplitude of the second harmonic wave cumulated in the propagation path of the primary wave is measured and the finite amplitude insert-substitution method is used in the conventional computer tomography (CT) technique. The filtered convolution algorithm is implemented using the amplitude of the second harmonic as the projection data, then the B/A tomography can be reconstructed. The B/A images for several biological samples are obtained. Besides, the image of porcine pathological liver tissue is studied and is compared with that of porcine normal liver tissue. These results show the potential applications of the nonlinearity parameter B/A in medical diagnosis.
声学非线性参数B/A是超声组织表征中的一个新参数。本文在对有限振幅超声波在类流体介质中传播进行理论分析的基础上，研制了一种用于非线性参数层析成像的实验系统。利用该系统，测量了基波传播路径上累积的二次谐波的振幅，并将有限振幅插入-替代法应用于传统的计算机断层扫描（CT）技术中。以二次谐波的振幅作为投影数据，实现滤波卷积算法，进而重建B/A层析图像。获得了几种生物样品的B/A图像。此外，对猪病理肝脏组织的图像进行了研究，并与猪正常肝脏组织的图像进行了比较。这些结果表明了非线性参数B/A在医学诊断中的潜在应用。
