Recent interest in ultrasound contrast agents (UCAs) as tools for quantitative imaging and therapy has increased the need for accurate characterization. Laboratory investigations are frequently undertaken in a water bath at room temperature; however, implications for in vivo applications are not presented. Acoustic investigation of a bulk suspension of SonoVue (Bracco Research, Geneva, Switzerland) was made in a water bath at temperatures of 20-45 degrees C. UCA characteristics were significantly affected by temperature, particularly between 20 and 40 degrees C, leading to an increase in attenuation from 1.7-2.5 dB, respectively (p = 0.002) and a 2-dB increase in scattered signal over the same range (p = 0.05) at an insonation pressure of 100 kPa. Optical data supported the hypothesis that a temperature-mediated increase in diameter was the dominant cause, and revealed a decrease in bubble stability. In conclusion, measurements made at room temperature require careful interpretation with regard to behavior in vivo.
Copyright 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.