Harmonic imaging using multitone nonlinear coding
Harmonic imaging using multitone nonlinear coding
复制标题
DOI：
10.1016/j.ultrasmedbio.2007.02.001
复制
发表时间：
2007-07-01
影响因子：
2.9
通讯作者：
Secomski, Wojciech
中科院分区：
文献类型：
--
作者：
Nowicki, Andrzei;Wojcik, Janusz;Secomski, Wojciech
我们提出了一种新的方法，利用组织的非线性特性，以提高对比度噪声比。在我们的新方法中，声源被激活的两个音突发（2.2和4.4 MHz），与专门设计的极化的个人音突发。这种新方法被称为多音调非线性编码（MNC），因为两个音调（及其幅度）的偏振选择，允许接收特性的优化，取决于组织的非线性特性。对在具有7 Np/m中心点MHz的吸收的组织状光泽介质中传播的两个音突发进行计算。通过扫描软组织中传播的入射脉冲和扫描浸没在水中的线体模，对该方法进行了实验验证。引入虚场的概念来解释脉冲反转和MNC的能力和性质，并对两种方法进行了比较。使用MNC与传统的谐波成像方法，其中的二次谐波是用来重建图像，获得的空间场分布的比较。结果表明，对于相同的峰值压力幅度，MNC的机械指数约低40%，横向分辨率好10%至30%，最令人鼓舞的是，信号增益比脉冲反转高8倍。（电子邮件：anowicki@ippt.gov.pl）（C）2007年世界医学和生物学超声联合会。
We present a new method that uses nonlinear properties of tissue to improve contrast-to-noise ratio. In our novel method, the acoustic source is activated with two tone-bursts (2.2 and 4.4 MHz), with specially designed polarization of the individual tone-burst. This new approach is called multitone nonlinear coding (MNC) because the choice of polarization of both tones (and their amplitudes), allowing optimization of the receiving properties, depends on the nonlinear properties of tissue. The calculations were done for two tone-bursts propagating in the tissue-like glossy medium with absorption of 7 Np/m center dot MHz. The method was experimentally verified by scanning the incident pulses propagating in soft tissue and by scanning the thread phantom immersed in water. The concept of the virtual fields was introduced to explain abilities and properties of pulse inversion and MNC and to compare the two methods. Comparison of the spatial field distribution obtained using MNC with the conventional harmonic imaging approach, in which the second harmonic is used to reconstruct the image, is presented. It was shown that, for the same peak pressure amplitude, the resulting mechanical index was about 40% lower for MNC, lateral resolution was 10% to 30% better and, what seems to be the most encouraging, the signal gain was up to eight times higher than pulse inversion. (E-mail: anowicki@ippt.gov.pl) (C) 2007 World Federation for Ultrasound in Medicine & Biology.