IUT Ville d'Avray, Université Paris Ouest Nanterre La Défense, 92 410 Ville d'Avray, France.
Comput Math Methods Med. 2013;2013:297463. doi: 10.1155/2013/297463. Epub 2013 Mar 20.
Ultrasound contrast imaging has provided more accurate medical diagnoses thanks to the development of innovating modalities like the pulse inversion imaging. However, this latter modality that improves the contrast-to-tissue ratio (CTR) is not optimal, since the frequency is manually chosen jointly with the probe. However, an optimal choice of this command is possible, but it requires precise information about the transducer and the medium which can be experimentally difficult to obtain, even inaccessible. It turns out that the optimization can become more complex by taking into account the kind of generators, since the generators of electrical signals in a conventional ultrasound scanner can be unipolar, bipolar, or tripolar. Our aim was to seek the ternary command which maximized the CTR. By combining a genetic algorithm and a closed loop, the system automatically proposed the optimal ternary command. In simulation, the gain compared with the usual ternary signal could reach about 3.9 dB. Another interesting finding was that, in contrast to what is generally accepted, the optimal command was not a fixed-frequency signal but had harmonic components.
超声造影成像技术得益于脉冲反相成像等创新模式的发展，为医学诊断提供了更准确的结果。然而，这种可以提高对比信噪比（CTR）的模式并不理想，因为频率是与探头一起手动选择的。但是，这个命令可以进行优化选择，但是需要有关换能器和介质的精确信息，而这些信息在实验中很难获得，甚至无法获得。事实证明，考虑到发生器的种类，优化会变得更加复杂，因为传统超声扫描仪中的电信号发生器可以是单极、双极或三极的。我们的目标是寻找最大化 CTR 的三进制命令。通过结合遗传算法和闭环，系统可以自动提出最佳的三进制命令。在模拟中，与通常的三进制信号相比，增益可以达到约 3.9dB。另一个有趣的发现是，与通常的观点相反，最佳命令不是固定频率的信号，而是具有谐波分量。
