Lencioni Riccardo, Cioni Dania, Bartolozzi Carlo
Division of Diagnostic and Interventional Radiology, Department of Oncology, Transplants, and Advanced Technologies in Medicine, University of Pisa, Via Roma 67, 56126 Pisa, Italy.
Eur Radiol. 2002 Jan;12(1):151-65. doi: 10.1007/s003300101022. Epub 2001 Sep 6.
The development of new US techniques that produce images based on nonlinear acoustic effects of US interaction with matter or microbubble contrast agents has opened new prospects for gray-scale US in native tissue and contrast imaging. Tissue harmonic imaging uses higher frequencies generated on propagation of the US beam through matter to improve image quality and resolve small anatomic structures and details, and is becoming a routine approach in US examination of many abdominal districts. Contrast-specific imaging techniques display enhancement of US agents in gray-scale with optimal contrast and spatial resolution, and offer high sensitivity either to microbubble movement or to microbubble destruction in dependence of the level of the applied acoustic peak pressure. Owing to the ability to exploit the microcirculation, contrast-specific techniques have enabled the evolution of contrast US from vascular imaging to the imaging of perfused tissues. Several studies have shown that these methods can substantially improve US detection and characterization of focal liver lesions, and promising results have been reported in other areas of investigation. This article reviews physical principles, technical issues, and clinical applications of tissue harmonic and contrast-specific imaging. It is foreseen that the new gray-scale US techniques will rapidly become a tool in numerous clinical scenarios.
基于超声与物质或微泡造影剂相互作用的非线性声学效应生成图像的新型超声技术的发展，为灰阶超声在原生组织成像和造影成像方面开辟了新前景。组织谐波成像利用超声束在穿过物质传播时产生的更高频率来提高图像质量，并分辨小的解剖结构和细节，正成为超声检查许多腹部区域的常规方法。特异性造影成像技术能以最佳的对比度和空间分辨率在灰阶下显示超声造影剂，并根据所施加的声学峰值压力水平，对微泡运动或微泡破坏具有高敏感性。由于能够利用微循环，特异性造影技术使超声造影从血管成像发展到灌注组织成像。多项研究表明，这些方法能显著改善超声对肝脏局灶性病变的检测及特征描述，并且在其他研究领域也已报道了有前景的结果。本文综述了组织谐波成像和特异性造影成像的物理原理、技术问题及临床应用。可以预见，新的灰阶超声技术将迅速成为众多临床场景中的一种工具。
