Voci P, Bilotta F, Merialdo P, Agati L
Department of Cardiac Surgery, La Sapienza University of Rome, Italy.
J Am Soc Echocardiogr. 1994 Jul-Aug;7(4):337-46. doi: 10.1016/s0894-7317(14)80191-0.
Myocardial opacification after intravenous injection of an echo-contrast agent is a major end point in contrast echocardiography, but it has not yet been obtained in human beings. We propose transesophageal contrast echocardiography as a clinical tool for the study of myocardial perfusion in human beings. Sonicated albumin microbubbles are bright ultrasound reflectors that cross the pulmonary vasculature after intravenous injection and show physiologic transit times through tissues. Transesophageal echocardiography uses ideal transducer frequency and acoustic window for in vivo detection of sonicated albumin microbubbles. We have studied 11 patients receiving peripheral vein bolus injection of sonicated albumin microbubbles during transesophageal echocardiography at baseline and during dipyridamole infusion. Images were recorded on videotape and digitized off-line. Quantitative measurements were made on 11 normally perfused myocardial segments by tracing a region of interest of greater than 100 pixels on frozen end-systolic frames, at baseline, and during dipyridamole infusion. Transpulmonary passage with full left ventricular cavity opacification was obtained in all injections. In 8 of 22 injections there was also transient left ventricular cavity attenuation. In all patients there was a marked opacification of the left ventricular outflow tract and aortic root. At baseline, mean signal intensity in the myocardium increased from 80 +/- 37 to 117 +/- 49 IU (p < 0.05) and during dipyridamole infusion increased from 84 +/- 28 to 146 +/- 36 IU (p < 0.001). The analysis of background-subtracted data showed that mean pixel intensity increased from baseline to dipyridamole contrast injection (from 37 +/- 15 to 62 +/- 19 IU; p < 0.01). The opacification of normally perfused left ventricular myocardium is feasible during transesophageal echocardiography because there is a significant increase in signal intensity versus background intensity. During dipyridamole infusion there is a further increase in signal intensity that probably reflects pharmacologically induced increase in myocardial blood flow.
静脉注射超声造影剂后心肌显影是超声心动图造影的主要终点，但尚未在人体中实现。我们提出经食管超声心动图造影作为研究人体心肌灌注的临床工具。超声处理的白蛋白微泡是明亮的超声反射体，静脉注射后可穿过肺血管系统，并显示出在组织中的生理通过时间。经食管超声心动图使用理想的换能器频率和声窗来体内检测超声处理的白蛋白微泡。我们研究了11例患者，在基线时和双嘧达莫输注期间经食管超声心动图检查时接受外周静脉推注超声处理的白蛋白微泡。图像记录在录像带上并离线数字化。通过在收缩末期冻结帧上追踪大于100像素的感兴趣区域，对11个正常灌注的心肌节段进行定量测量，测量在基线时和双嘧达莫输注期间进行。所有注射均获得了经肺通过并使左心室腔完全显影。在22次注射中有8次还出现了左心室腔的短暂衰减。所有患者的左心室流出道和主动脉根部均有明显显影。在基线时，心肌的平均信号强度从80±37增加到117±49 IU（p<0.05），在双嘧达莫输注期间从84±28增加到146±36 IU（p<0.001）。对减去背景的数据进行分析表明，平均像素强度从基线到双嘧达莫造影剂注射时增加（从37±15增加到62±19 IU；p<0.01）。在经食管超声心动图检查期间，正常灌注的左心室心肌显影是可行的，因为与背景强度相比，信号强度有显著增加。在双嘧达莫输注期间，信号强度进一步增加，这可能反映了药物诱导的心肌血流增加。
