Silverman R H, Rondeau M J, Lizzi F L, Coleman D J
Margaret M. Dyson Vision Research Institute, Department of Ophthalmology, Cornell University Medical College, New York, USA.
Ophthalmology. 1995 May;102(5):837-43. doi: 10.1016/s0161-6420(95)30948-7.
High-frequency ultrasound allows high-resolution imaging of anterior segment anatomy and pathology. Acoustic echo data, however, contain information relating to the microanatomic structure of the interrogated tissue which is not evident in B-mode images. The aim of this study is to develop imaging techniques to demonstrate and quantify the distribution of acoustic scattering properties in ocular tissues in three dimensions.
A tumor of the iris and a hyphema were scanned using a 50-MHz ultrasound probe mounted on a computer-controlled two-axis positioning system. Scan data from sequential parallel planes were used to make three-dimensional reconstructions. Digital signal processing and a mathematical model of acoustic backscatter then were used to represent the effective size and acoustic concentration of scattering elements using a false color representation superimposed on B-mode images.
Three-dimensional reconstructions improved appreciation of the size and extent of pathology and allowed computation of tissue volumes. Parameter images demonstrated distinctive differences between diffuse and organized blood and allowed quantification of tumor scattering properties.
Three-dimensional imaging of the anterior segment with high-frequency ultrasound allows construction of perspective images, which adds to the already significant clinical use of individual high-resolution B-mode images. Acoustic backscatter properties determined by tissue microstructure can be computed from echo data and represented in false color in three-dimensional reconstructions.
高频超声可实现眼前节解剖结构和病理状况的高分辨率成像。然而，声学回波数据包含与被检查组织的微观解剖结构相关的信息，这些信息在B模式图像中并不明显。本研究的目的是开发成像技术，以三维方式展示和量化眼组织中声学散射特性的分布。
使用安装在计算机控制的双轴定位系统上的50兆赫超声探头对虹膜肿瘤和前房积血进行扫描。来自连续平行平面的扫描数据用于进行三维重建。然后，利用数字信号处理和声学反向散射的数学模型，通过叠加在B模式图像上的伪彩色表示来呈现散射元件的有效尺寸和声学浓度。
三维重建提高了对病理状况大小和范围的认识，并能够计算组织体积。参数图像显示了弥漫性和有组织的血液之间的明显差异，并能够量化肿瘤的散射特性。
高频超声对眼前节进行三维成像可构建透视图像，这增加了个体高分辨率B模式图像已有的重要临床应用价值。由组织微观结构决定的声学反向散射特性可从回波数据中计算得出，并在三维重建中以伪彩色表示。
