Frijlink Martijn E, Goertz David E, van Damme Luc C A, Krams Rob, van der Steen Antonius F W
Biomedical Engineering, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
IEEE Trans Ultrason Ferroelectr Freq Control. 2006 Oct;53(10):1844-52. doi: 10.1109/tuffc.2006.116.
Tissue harmonic imaging (THI) has been shown to increase image quality of medical ultrasound in the frequency range from 2 to 10 MHz and might, therefore, also be used to improve image quality in intravascular ultrasound (IVUS). In this study we constructed a prototype IVUS system that could operate in both fundamental frequency and second harmonic imaging modes. This system uses a conventional, continuously rotating, single-element IVUS catheter and was operated in fundamental 20 MHz, fundamental 40 MHz, and harmonic 40 MHz modes (transmit 20 MHz, receive 40 MHz). Hydrophone beam characterization measurements demonstrated the build-up of a second harmonic signal as a function of increasing pressure. Imaging experiments were conducted in both a tissue-mimicking phantom and in an atherosclerotic animal model in vivo. Acquisitions of fundamental 20 and 40 MHz and second harmonic acquisitions resulted in cross sections of the phantom and a rabbit aorta. The harmonic results of the imaging experiments showed the feasibility of intravascular THI with a conventional IVUS catheter both in a phantom and in vivo. The harmonic acquisitions also showed the potential of THI to reduce image artifacts compared to fundamental imaging.
组织谐波成像（THI）已被证明可提高2至10兆赫兹频率范围内医学超声的图像质量，因此也可用于改善血管内超声（IVUS）的图像质量。在本研究中，我们构建了一个原型IVUS系统，该系统可以在基波频率和二次谐波成像模式下运行。该系统使用传统的连续旋转单元素IVUS导管，并在20兆赫兹基波、40兆赫兹基波和谐波40兆赫兹模式下运行（发射20兆赫兹，接收40兆赫兹）。水听器波束特性测量表明，二次谐波信号随着压力增加而增强。成像实验在组织模拟体模和体内动脉粥样硬化动物模型中进行。采集20和40兆赫兹基波以及二次谐波后，得到了体模和兔主动脉的横截面。成像实验的谐波结果表明，使用传统IVUS导管在体模和体内进行血管内THI是可行的。与基波成像相比，谐波采集还显示了THI减少图像伪像的潜力。
