Petrick J, Zomack M, Schlief R
Clinical Development Diagnostics, Schering AG Berlin, Germany.
Invest Radiol. 1997 Apr;32(4):225-35. doi: 10.1097/00004424-199704000-00006.
Based on the echo-enhancing effect of microbubbles, various agents have been developed to improve the diagnostic confidence in patients with inadequate Doppler signals. In the clinical trials of the echo enhancer Levovist, there were a few isolated cases in which the maximum flow velocities of the enhanced Doppler spectra appeared to higher than the velocities in the nonenhanced baseline spectra. This raised the concern that echo enhancement could give a false indication of maximum flow velocity. This study investigated whether a systematic association between echo enhancement and velocity shift exists.
A pulsatile flow phantom that simulated the elasticity of blood vessels and the acoustic attenuation of extravascular tissue was used to compare enhanced with unenhanced Doppler spectra under accurately reproducible flow conditions. The experiments were carried out with varied sound attenuation and evaluated with dedicated spectral analysis software that included a special averaging tool.
Levovist enhanced the Doppler signal by 16 to 31 dB, and the enhanced and unenhanced power spectra presented identical distribution of spectral power density under all flow conditions.
The measurements gave no evidence that echo enhancement with Levovist falsifies the Doppler measurement of flow velocity.
基于微泡的回声增强效应，已研发出多种试剂以提高对多普勒信号不足患者的诊断可信度。在回声增强剂声诺维的临床试验中，有少数孤立病例显示，增强后的多普勒频谱最大流速似乎高于未增强的基线频谱流速。这引发了人们对回声增强可能会给出最大流速错误指示的担忧。本研究调查了回声增强与流速偏移之间是否存在系统性关联。
使用一个模拟血管弹性和血管外组织声衰减的脉动血流模型，在精确可重复的血流条件下比较增强和未增强的多普勒频谱。实验在不同声衰减条件下进行，并使用包含特殊平均工具的专用频谱分析软件进行评估。
声诺维使多普勒信号增强了16至31分贝，并且在所有血流条件下，增强和未增强的功率谱呈现出相同的频谱功率密度分布。
测量结果未提供证据表明声诺维的回声增强会使流速的多普勒测量结果出现偏差。
