组织超声谐波特性的Nakagami分布统计特征研究  

Characterization for Ultrasonic Harmonic of Tissue Based on Nakagami Distribution

作　　者：武柯言 张榆锋[1] 赵征鹏 高莲[1] 章克信[2] 张俊华[1] 陈建华[1] WU Ke-yan;ZHANG Yu-feng;ZHAO Zheng-peng;GAO Lian;ZHANG Ke-xin;ZHANG Jun-hua;CHEN Jian-hua(Department of Electronic Engineering,Information School,Yunnan University,Kunming,Yunnan 650091,China;The Second Affiliated Hospital of Kunming Medical University,Kunming,Yunnan 650031,China)

机构地区：[1]云南大学信息学院电子工程系,云南昆明650091 [2]昆明医科大学第二附属医院,云南昆明650031

出　　处：《电子学报》2018年第7期1639-1643,共5页Acta Electronica Sinica

基　　金：国家自然科学基金(No.61561049;No.81771928)

摘　　要：研究了超声回波信号中二次谐波包络信号的Nakagami分布参数与非线性系数之间的对应关系,以获得更准确的组织非线性定量特征.将超声回波射频信号的基/谐波成分进行分离,获取基波和二次谐波成分的包络信号,分别计算并比较信号的Nakagami分布参数.仿真结果表明,对于不同的非线性系数,二次谐波包络信号的分布参数相互分离,特别是非线性系数β在3~6的范围内具有显著的差异,而对应的基波的差异性不显著.离体组织实验中,与脂肪相比,肝和脑的基波的平均功率ω和形状因子μ的相对差异分别为7.3%和0.03%及2.0%和4.3%;谐波的ω和μ的相对差异分别为8.3%和19.4%及7.0%和34.0%.结果进一步验证了仿真结果的有效性和正确性.综上所述,不同非线性组织超声回波信号中,二次谐波包络信号的Nakagami分布参数具有显著差异,可据此定量分析生物组织的非线性特征.The relationship between the nonlinear coefficient and parameter values of Nakagami distribution from the envelopes of fundamental and second harmonic signals are investigated to obtain more accurate nonlinear quantitative characteristics of tissue. The envelopes of fundamental and second harmonic signals are separated from the whole echoed RF signals using Butterworth high-pass filter. Then the Nakagami distribution parameters of the envelope signals are calculated and compared. The simulation results showthat for different values of the nonlinear coefficients,the values of distribution parameters of the fundamental envelope signals are aliasing. On the contrary,the parameter values of second harmonic are mutually separating,especially for the nonlinear coefficients ranged from 3 to 6. In vitro experiments,compared with fat tissue,the relative differences of Nakagami parameter ω and μ of the fundamental envelope signals for liver and brain tissue are 7. 3%,0. 03% and 2. 0%,4. 3%,respectively; however the relative differences of 2 ndharmonic envelope signals are 8. 3%,19. 4% and 7. 0%,34. 0%,respectively. The results of vitro experiments verify the effectiveness and correctness of the simulation results. In conclusion,the parameter values of Nakagami distribution for the second harmonic envelope signals from different degrees of nonlinearity in tissue are significantly different. According to this,we can quantitatively analyze the nonlinear characteristics of biological tissue.

关 键 词：Nakagami分布 非线性 超声谐波信号 组织特性 

分 类 号：TN911.7[电子电信—通信与信息系统]