QUANTIFICATION OF THE ENHANCED BACKSCATTER PHENOMENON FROM AN INTRAVENOUS AND AN INTRAARTERIAL CONTRAST AGENT

The phenomenon of enhanced backscatter from myocardial contrast agents was studied using two examples, a robust thicker-walled, intra-arteri al agent (AIP 201) and a smaller thinner-walled, intravenous agent (Qu antison(TM)). Both agents are composed of albumin-encapsulated microbu bbles. Samples of the agents were inserted into an in vitro phantom an d insonated under different scanning regimes. Upon insonation, Quantis on(TM) exhibited a pronounced increase in mean backscatter at medium a nd low concentrations, which decreased dramatically with increasing nu mber of frames of insonation. At high concentrations, no dramatic decr ease or increase in mean backscatter was observed over the period of t he experiment. AIP 201 exhibited an overall decrease in mean backscatt er with increasing number of frames of insonation. These results sugge st that the difference in size and wall thickness of the contrast micr ocapsules can significantly affect the behaviour of the contrast agent s in an ultrasound held. (C) 1998 World Federation for Ultrasound in M edicine & Biology.