Weissman N J, Cohen M C, Hack T C, Gillam L D, Cohen J L, Kitzman D W
Georgetown Medical Center, Washington DC, USA.
Am Heart J. 2000 Mar;139(3):399-404. doi: 10.1016/s0002-8703(00)90082-6.
In current practice, contrast echocardiography is performed with single or multiple bolus injections, which often result in an uncontrolled period of attenuation followed by transient left ventricular opacification (LVO). Because a "slow bolus" appears to reduce attenuation and prolong LVO, we hypothesized that a controlled infusion of contrast might provide a more uniform contrast effect with less attenuation and longer contrast duration.
We sought to test the hypothesis by using an infusion of contrast (DEFINITY [perflutren], The DuPont Pharmaceuticals Co, Medical Imaging, North Billerica, Mass) that is stable when diluted in saline in a randomized, multicenter, controlled, crossover trial. Sixty-four patients with poor noncontrast images were recruited at 3 centers and randomly assigned to 2 single "slow" bolus injections of contrast (10 microL/kg each over a period of 30 to 60 seconds) or an infusion (1. 3 mL in 50 mL normal saline initially at 4.0 mL/min) of contrast. Patients then returned within 24 to 72 hours for the alternative form of contrast delivery. Three independent experienced echocardiographers viewed 30 seconds of videotape for all optimal baseline and optimal contrast images to score LVO and qualitatively assessed endocardial border evaluability. The duration of adequate LVO then was independently assessed by review of the entire videotape. Three independent sonographers traced single-frame, digitally captured images to measure the length of the contiguous endocardial border visualized. Both bolus and infusion administration demonstrated improved LVO (>90% by all blinded readers, P <.01) and endocardial border visualized (mean increase of 1.8 to 4.7 cm at both end-diastole and end-systole, all P <.05) as compared with baseline images. However, contrast infusion resulted in a longer duration of LVO (range of mean durations for each reader, 158 to 174 seconds longer, P <.05) and a shorter duration of attenuation (18 to 54 seconds, P <.05) compared with either bolus injection. There were no severe adverse events with contrast infusion.
Contrast echocardiography delivered as an infusion optimizes the contrast effect by decreasing the attenuation period, extending the LVO duration, and providing a uniform contrast effect that may be useful in obtaining multiple echocardiographic views, stress echocardiography, myocardial perfusion imaging, and applications in which blood flow must be quantified.
在当前的实践中，超声心动图造影是通过单次或多次团注进行的，这通常会导致一段无法控制的衰减期，随后是短暂的左心室显影（LVO）。由于“缓慢团注”似乎可以减少衰减并延长LVO，我们推测，控制性注入造影剂可能会提供更均匀的造影效果，减少衰减并延长造影持续时间。
我们试图通过在一项随机、多中心、对照、交叉试验中使用一种在生理盐水中稀释后稳定的造影剂注入（德弗尼[全氟显]，杜邦制药公司，医学影像部，马萨诸塞州北比勒里卡）来验证这一假设。在3个中心招募了64例非造影图像质量较差的患者，并将其随机分配接受2次单次“缓慢”团注造影剂（每次10 μL/kg，在30至60秒内注入）或注入（最初在50 mL生理盐水中注入1.3 mL，速度为4.0 mL/min）造影剂。然后，患者在24至72小时内返回接受另一种造影剂给药方式。3名独立且经验丰富的超声心动图医师查看了所有最佳基线和最佳造影图像的30秒录像带，以对LVO进行评分，并定性评估心内膜边界的可评估性。然后，通过查看整个录像带独立评估足够的LVO持续时间。3名独立的超声检查人员追踪数字采集的单帧图像，以测量可视化的连续心内膜边界的长度。与基线图像相比，团注和注入给药方式均显示LVO有所改善（所有盲法读者的改善率均>90%，P<.01），心内膜边界可视化程度提高（舒张末期和收缩末期的平均增加幅度为1.8至4.7 cm，所有P<.05）。然而，与任何一种团注方式相比，注入造影剂导致LVO持续时间更长（每位读者的平均持续时间范围长158至174秒，P<.05），衰减持续时间更短（18至54秒，P<.05）。注入造影剂未发生严重不良事件。
通过注入方式进行超声心动图造影可通过减少衰减期、延长LVO持续时间并提供均匀的造影效果来优化造影效果，这在获取多个超声心动图视图、负荷超声心动图、心肌灌注成像以及必须对血流进行量化的应用中可能是有用的。
