组织的超声背向散射频谱特性研究

超声用于人体疾病诊断已取得肯定的作用,其发展方向为灰阶图像和超声组织定征研究,组织定征研究包括衰减、散射、吸收和频谱分析,频谱分析方法不仅能获得超声回波的幅值信息,而且能获得相位和频率信息、因而能更全面地反映组织结构特征。本研究包括:(a)超声频谱分析系统的建立;(b)随机介质频谱特性的测量;(c)采样深度对频谱特性的影响;(d)生物体实验模型的建立。研究结果表明:(1)散射体密度高的介质其频率分量幅值都相应提高;(2)散射体尺寸小的介质对频率变化的灵敏度高;(3)散射体结构由密变疏其频率峰值差异变大;(4)正常组织的不同器官之间,正常组织与病变组织之间.有一定的特异性。

Research on Frequency Spectrum Characterization of Ultrasonic Back Scattering in Tissue

Comment on the fact that ultrasound pulse back scattered from soft tissue has diagnostic value led to two distinct directions of development. The first was the development of grey-scale imaging devices. The second was ultrasonic tissue characterization. The tissue characterization based on analysis of reflected RF signals includes estimation of attenuation,scattering,absorption and spectrum analysis. The method of spectrum analysis not only retains amplitude information but also phase and frequency information. It will enhance the diagnostic capability of ultrasonic imaging system.Our research includes : (a) To set a frequency spectrum analysis system; (b)To measure the spectrum from a set of random media;(c)To consider the effect of sampling depth; (d) To set examination models of different tissues of normal human and rabits livers,kidneys,galls,while the toxicohepatitis of rabets is used as a patient model,For rabit,measurements in vivo and vitro are included.Our research findings show : (1) The media with more scatters were observed to bigger amplitude over the full available signal bandwidth. (2)Smaller size scatters are more sensitive to frequency. (3) The largest water content scatters show biggest difference in peak between 2. 7MHz and 3. 7MHz. (4) Differences between the spectrum characterization of different tissues or normal and diseased tissue have been showed. The results correlate with acoustic characters.