In vitro evaluation of a new echographic contrast agent.
ABSTRACT So far, intravenously injected echographic contrast agents have not been able to overcome the lung circle, and their use was confined to the study of right-sided heart abnormalities. A new agent that is able to pass the pulmonary barrier has been manufactured, and it is currently under investigation in ophthalmology.
A saccharide-based contrast agent (SHU 454) that is not able to overcome the lung filter has been compared in vitro with a new saccharide-based contrast agent (SHU 508 A) that is able to overcome the pulmonary barrier. They have been diluted in saline solution, and the reflectivity of the solution and the eventual sound attenuation have been studied with standardized A scan and a tissue model.
The solution with SHU 508 showed a higher reflectivity that lasted longer, without significant sound attenuation.
The long-lasting period of the increased reflectivity will allow to better evaluate the normal and pathological vascular network in the eye and orbit, such as the evaluation of the effectiveness of conservative treatment in cases of malignant melanoma with a spread of the indications of standardized echography to other fields of ophthalmology.
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ABSTRACT: The intravenous injection of an ultrasound contrast agent can enhance signals from blood flow. Broad toxicological and pharmaceutical studies in animals confirmed the safety and efficacy of an ultrasound contrast agent made of microparticles of galactose with stabilised microbubbles in watery suspension (SH U 508 A). In this paper 10 patients with different malignant orbital and ocular tumours have been evaluated with an echo colour Doppler machine before and after the injection of SH U 508 A. An enhancement of the Doppler signals in the lesions in different degrees has been detected. This echographic contrast agent seems to be very important not only in the evaluation of vascular lesions, but also in evaluating the effectiveness of radiotherapy in malignant tumours and could spread the echographic indications in several other ophthalmic fields.British Journal of Ophthalmology 12/1994; 78(11):823-6. · 2.73 Impact Factor
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ABSTRACT: Evidence that microbubbles are the main sources of ultrasound contrast in injected solutions has been largely indirect. To investigate this directly, we examined freshly agitated indocyanine green, freshly agitated water, commercially prepared precision microbubbles (diameter 75 +/- 25 mu) in gelatin, carbonated water, "degassed" indocyanine green solution, and "degassed" water in one or more of four different assay systems. Only fluids with microbubbles produced ultrasound contrast. Injected contrast material rose in a water bath at a rate that identified it as being caused by microbubbles. Indocyanine green and gelatin surface tensions were measured and found to be low (43 dynes/cm2), thus explaining their tendency to stabilize the microbubbles that cause ultrasound contrast effect when injected and to hold foam after agitation. The force of hand injections (force similar to that used clinically through catheters and 19-gauge or 23-gauge needles) was below the force needed to cause cavitation or ultrasound contrast effect. Microbubble content could be quantified by the decrease in amplitude of the echo from a structure distant to the microbubbles. We conclude that that the ultrasound contrast effect seen in peripherally injected fluids is caused by microbubbles present in the injectant. The contrast is not due to cavitation at needle tips, and it can be quantified over a limited range. Improved design for a peripheral contrast agent is suggest.Journal of Clinical Ultrasound 05/1980; 8(2):121-7. · 0.70 Impact Factor
- Investigative Radiology 01/1989; 7(6):500-5. · 5.46 Impact Factor