Evans David H
Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.
Front Neurol Neurosci. 2006;21:1-18. doi: 10.1159/000092379.
Ultrasound is an important technique for studying neurovascular pathology. As with any measurement or imaging technique, it has strengths and weaknesses, and there are a number of potential pitfalls for those interpreting its results. This chapter describes the basic physics and instrumentation behind both imaging and Doppler ultrasound techniques, with a special emphasis on their application to the cerebral circulation. The nature of ultrasound propagation in tissue is described, and the speed of ultrasound, its attenuation, and its behaviour at boundaries of various types are discussed. A description of pulse-echo B-mode techniques includes a section on transducers and artefacts. Doppler ultrasound is particularly important in the study of blood flow, and embolus detection, and its basic principles and various instrument types are described. The uses of transcranial Doppler for the measurement of velocity, flow changes, cerebrovascular resistance, and embolus detection are described. Finally the safety of ultrasound techniques in the context of cerebral vessels and in particularly transcranial Doppler is discussed.
超声是研究神经血管病理学的一项重要技术。与任何测量或成像技术一样，它有优点和缺点，对于解读其结果的人来说存在一些潜在的陷阱。本章介绍了成像超声技术和多普勒超声技术背后的基本物理原理和仪器设备，特别强调了它们在脑循环中的应用。描述了超声在组织中的传播特性，并讨论了超声的速度、衰减及其在各种类型边界处的行为。脉冲回波B型技术的描述包括换能器和伪像部分。多普勒超声在血流研究和栓子检测中尤为重要，并描述了其基本原理和各种仪器类型。介绍了经颅多普勒在测量速度、血流变化、脑血管阻力和栓子检测方面的用途。最后讨论了超声技术在脑血管领域尤其是经颅多普勒方面的安全性。
