Myocardial perfusion imaging by contrast echocardiography with use of intracoronary sonicated albumin in humans

Abstract

Sonicated albumin has been proposed as a near ideal echocardiographic contrast agent with little myocardial toxicity or hemodynamic effect. Its use has not yet been reported in humans, partly because of difficulties in preparation. With use of the newly modified sonication method, 10 ml of 5% albumin was sonicated for 75 s with a 5.0 ml slow infusion of air. This resulted in microbubbles with a mean diameter (+/- SD) of 5 +/- microns). Fourteen patients undergoing routine coronary angiography were studied. One patient had normal coronary arteries; the other 13 had significant coronary artery disease. In a subgroup of nine patients, sonicated albumin and sonicated diatrizoate meglumine sodium (microbubble diameter 9 +/- 3 microns) were injected several minutes apart, using the same technique. Videodensity-time curves were obtained from a region of interest in the myocardium. Corrected peak contrast intensity (baseline contrast intensity subtracted from peak contrast intensity, gray scale U/pixel) for sonicated albumin and for sonicated diatrizoate meglumine sodium was 51 +/- 26 and 52 +/- 19, respectively (p = 0.89). Washout half-time (T1/2) for the two agents was 5.5 +/- 4.5 and 16.0 +/- 12.2 s, respectively (p = 0.01). One patient with unstable angina experienced transient chest pain after repeated albumin injections. No electrocardiographic changes, blood pressure changes or wall motion abnormalities were observed. Administered by intracoronary injection, sonicated 5% albumin is a safe and effective echocardiographic contrast agent for myocardial perfusion imaging, yielding excellent myocardial contrast with physiologic washout time.

Combined Assessment of Myocardial Perfusion and Regional Left Ventricular Function by Analysis of Contrast-Enhanced Power Modulation Images

“…1,7 Contrast echocardiography is increasingly referred to as a technique that could potentially allow quantification 4 -6 or at least imaging of myocardial perfusion. 2,3,8,16,17 This goal, however, still remains a great challenge. 18 Although LV opacification for improved endocardial visualization is better established than perfusion imaging, it is qualitative, because there is no technique to automatically detect the endocardial border from contrast-enhanced images.…”

Vascular Gene Transfer of Phosphomimetic Endothelial Nitric Oxide Synthase (S1177D) Using Ultrasound-Enhanced Destruction of Plasmid-Loaded Microbubbles Improves Vasoreactivity

“…Gas-filled albumin microbubbles were created by slight modification to the method described previously by Reisner et al 13 Briefly, 2 mL of a 5% solution of human albumin (BSD BW) containing 20 g of DNA (propidium iodide-bounded DNA, pcDNA-LacZ, pcDNA 3.1, or pcDNA-eNOS S1177D) was drawn into a 5-mL syringe, which was connected by a 3-way tap to another 5-mL syringe containing 2 mL of gas (room air or perfluorocarbon). The DNA-albumin solution was sonicated with a sterile (20 kHz) sonicating horn (Sonifier Desintegrator model W-450, Branson Ultrasonic S.A.), which was introduced into the syringe.…”

Combination of contrast with stress echocardiography: A practical guide to methods and interpretation

“…Even when optimal microbubble delivery to the myocardium is achieved with invasive coronary [1] or aortic root [2] injections, detection of reliable myocardial opacification using standard 2D imaging is difficult. Whilst this partly reflects difficulty distinguishing bright, grey scale echo signals from the myocardial tissue from those of micro-bubbles within the myocardial micro-circulation, the problem is multi-factorial and has been overcome by the development of contrast specific imaging modalities, which exploit the unique interaction between the ultrasound field and micro bubbles[3] to maximise the received contrast backscatter and minimise myocardial tissue backscatter.…”