Foster F S, Knapik D A, Machado J C, Ryan L K, Nissen S E
Sunnybrook Health Science Centre, Toronto, Ontario, Canada.
Semin Interv Cardiol. 1997 Mar;2(1):33-41.
Intravascular ultrasound is playing an increasingly important role in the clinical management of coronary interventions. In the past few years the technology for intracoronary ultrasound, in response to clinical pressure, has moved towards lower profile probes with improved handling. While new catheter designs are markedly improved on their predecessors, image quality has not seen significant gains due to the primitive nature of the ultrasound transducer designs. In this article, the potential for improving image quality by increasing the frequency and focusing the ultrasound beam is explored. Basic aspects of transducer implementation are discussed and the acoustic properties of vascular tissues and blood are reviewed. A variety of instruments are used to image coronary and femoral arteries at frequencies ranging from 40 to 200 MHz. These studies serve to illustrate the trade-offs in the development of high frequency IVUS systems. There would appear to be no fundamental reason why frequencies in excess of 50 MHz could not be implemented. Studies using prototype IVUS instruments in the 50 MHz range demonstrate significant improvements in image quality.
血管内超声在冠状动脉介入治疗的临床管理中发挥着越来越重要的作用。在过去几年中，冠状动脉内超声技术迫于临床压力，已朝着更小巧、操控性更佳的探头发展。虽然新型导管设计相比其前代产品有了显著改进，但由于超声换能器设计的原始特性，图像质量并未取得显著提升。在本文中，探讨了通过提高频率和聚焦超声束来改善图像质量的潜力。讨论了换能器实现的基本方面，并回顾了血管组织和血液的声学特性。使用各种仪器在40至200MHz的频率范围内对冠状动脉和股动脉进行成像。这些研究旨在说明高频血管内超声系统开发中的权衡取舍。似乎没有根本原因表明不能采用超过50MHz的频率。使用50MHz范围内的血管内超声仪器原型进行的研究表明，图像质量有了显著改善。
