TABLE OF CONTENTS Dong Zhang and Xiu-fen Gong
Institute of Acoustics, Lab. of Modern Acoustics Nanjing University, Nanjing 210093, China dzhang@ nju.edu.cn
Acoustic nonlinear imaging has brought about significant improvements in image quality by taking advantage of the nonlinear components. This article reviews works of acoustic nonlinear imaging for biological tissues in Nanjing University, including acoustic nonlinearity parameter B/A imaging, tissue harmonic imaging by using the multi-phase-coded-pulse technique and super harmonic imaging. Theoretical analysis and experimental imaging of biological tissues by using these methods are presented.
Ultrasound imaging has been widely accepted for clinical diagnosis because of its capability to provide important information on the diseased state of the tissues in a human body non-invasively and non-destructively. In recent years, ultrasound image quality has been greatly improved due to advances in technology and introduction of new techniques, such as tissue harmonic imaging [1 3]. The acoustic nonlinear effects in biological tissues at biomedical frequencies and intensities were first theoretically predicted and experimentally demonstrated [4 5]. The second and higher harmonic components are generated as ultrasound propagates through biological tissues due to the phenomenon of nonlinear sound propagation. Tissue harmonic imaging uses ultrasound at twice the transmitted frequency to form the image, unlike the fundamental imaging that uses ultrasound at the transmitted frequency to form the image. Although it is superior to fundamental imaging mode due to improvement of the spatial resolution and suppression of side lobe levels, two typical shortcomings are associated with this technique. One is that the low signal-to-noise ratio...
