Testing a new surfactant in a widely-used blood mimic for ultrasound flow imaging

Background: A blood-mimicking fluid developed by Ramnarine etal. has been widely used in flow phantoms for ultrasound flow imaging research, and it has also been cited by IEC 61685 as a reference for making blood-mimicking fluid.However, the surfactant material Synperonic N in this blood-mimicking fluid recipe is phased out from the European market due to environmental issues. The aim of this study is to test whether Synperonic N can be substituted by biodegradable Synperonic A7 in making blood-mimicking fluid for ultrasound flow imaging research. Methods and materials: A flow phantom was fabricated to test the blood-mimicking fluid with Synperonic N and Synperonic A7 as surfactants separately. Doppler images and velocity data were collected using a clinical ultrasound scanner under constant and pulsatile flows; and images and measured velocities were compared. Results: It was found that both blood mimics can provide exactly the same images under spectral Doppler ultrasound and colour Doppler ultrasound in terms of their image qualities. The maximum velocities under constant flow were measured by the spectral Doppler ultrasound as 0.4714 +/- 0.001m.s(-1) and 0.4644 +/- 0.001m.s(-1) for blood-mimicking fluid with Synperonic N and blood-mimicking fluid with Synperonic A7, respectively. Measured velocities using the two different blood-mimicking fluids were statistically different (p<0.001), but this difference was less than 2%. The Synperonic A7 can be used as a substitute for Synperonic N as a surfactant material in making the blood-mimicking fluid for ultrasound flow imaging research.