Photoacoustic and ultrasound imaging contrast enhancement using a dual contrast agent

Abstract

The complementary information provided by the ultrasound and photoacoustic imaging modalities has sparked their use in combination in recent years. We introduce a dual contrast agent capable of providing image contrast enhancement for both modalities simultaneously. The dual contrast agent is a small liquid perfluorocarbon droplet encased with bovine serum albumin and loaded with plasmonic nanoparticles. The plasmonic metal nanoparticles themselves act as a photoacoustic contrast agent. Furthermore, the perfluorocarbon droplet creates acoustic impedance mismatch between itself and the surrounding tissue, allowing it to act as an ultrasound contrast agent. Experiments demonstrating the performance of this dual contrast agent in ultrasound and photoacoustic imaging are presented. Differences in contrast mechanisms of the dual agent are highlighted, and finally, the applications for the agent are discussed.