Villarraga H R, Foley D A, Aeschbacher B C, Klarich K W, Mulvagh S L
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA.
J Am Soc Echocardiogr. 1997 Oct;10(8):783-91. doi: 10.1016/s0894-7317(97)70036-1.
Inhomogenous opacification of cardiac chambers has been frequently observed after intravenous administration of long-persisting echocardiographic contrast agents. We observed this phenomenon to be most pronounced at high acoustic powers with incomplete opacification of the left ventricular apex and left ventricular outflow tract. Reducing the acoustic energy to which the contrast was exposed by decreasing transmit power or intermittently suspending insonification resulted in homogenous opacification of the entire left ventricular cavity. We systematically examined the effect of varying insonification power on the persistence of three investigational ultrasound contrast agents in both in vitro and in vivo models. We found an inverse relationship between the insonifying power and the persistence of the contrast agents. Contrast intensity decay could be reduced either by decreasing exposure to ultrasound by minimizing the transmit power of the system or by intermittently suspending ultrasound generation (triggering). Minimization of ultrasound contrast exposure to ultrasound energy thus improves echocardiographic contrast duration and homogeneity.
静脉注射长效超声心动图造影剂后，经常观察到心腔内出现不均匀的造影剂增强。我们观察到，在高声功率下，这种现象最为明显，左心室心尖和左心室流出道造影剂增强不完全。通过降低发射功率或间歇性暂停超声照射来降低造影剂所暴露的声能，可使整个左心室腔均匀显影。我们在体外和体内模型中系统地研究了不同超声照射功率对三种研究用超声造影剂持久性的影响。我们发现超声照射功率与造影剂的持久性呈反比关系。通过最小化系统发射功率来减少超声暴露，或通过间歇性暂停超声产生（触发），均可减少造影剂强度衰减。因此，将超声造影剂暴露于超声能量降至最低，可改善超声心动图造影的持续时间和均匀性。
