von Bibra H, Bone D, Voigt J U, Niklasson U, Wranne B, Rydén L
Clin. Physiology, Thoracic Clinics Karolinska Hospital, Stockholm.
Z Kardiol. 2000;89 Suppl 1:86-96. doi: 10.1007/s003920070129.
The intravenous application of an ultrasound contrast agent induces enhanced display of blood in all its pathways. Within cardiology, this principle is mainly utilized for signal enhancement of color Doppler and spectral Doppler in order to improve quantification of congenital and acquired valvular lesions and also for improved endocardial delineation during stress tests and in the evaluation of LV function. The new domaine of myocardial perfusion imaging by contrast echocardiography, however, needed profound technical developments before realization of the clinical potential could even be conceived. These are based on the complex reactions of microbubbbles in the acoustic field in order to allow the sensitive and bubble specific display of intramyocardial contrast effects. The presently available acquisition techniques, second harmonic imaging and harmonic power Doppler, demonstrate significant improvements if compared to traditional fundamental 2-d echocardiography; however, they are still subjected to important limitations. There are many anatomical, physiological, and technical reasons for insufficient display of intramyocardial microbubbles, the most important one being attenuation. It is hoped that the most recently developed imaging modality, pulse inversion technique, allows the necessary diagnostic accuracy and reproducibility in myocardial perfusion imaging.
静脉注射超声造影剂可增强显示血液在所有路径中的情况。在心脏病学领域,这一原理主要用于增强彩色多普勒和频谱多普勒信号,以改善先天性和后天性瓣膜病变的量化,还用于在负荷试验期间及评估左心室功能时更好地勾勒心内膜。然而,在实现心肌灌注成像的临床潜力之前,超声心动图心肌灌注成像这一新领域需要深入的技术发展。这些技术发展基于微泡在声场中的复杂反应,以便能够敏感且特异性地显示心肌内的造影效果。与传统的二维基波超声心动图相比,目前可用的采集技术,即二次谐波成像和谐波能量多普勒,显示出显著改进;然而,它们仍存在重要局限性。心肌内微泡显示不足有许多解剖学、生理学和技术方面的原因,其中最重要的是衰减。希望最近开发的成像模式——脉冲反转技术,能在心肌灌注成像中提供必要的诊断准确性和可重复性。