@article{sheeran_rojas_puett_hjelmquist_arena_dayton_2015, title={CONTRAST-ENHANCED ULTRASOUND IMAGING AND IN VIVO CIRCULATORY KINETICS WITH LOW-BOILING-POINT NANOSCALE PHASE-CHANGE PERFLUOROCARBON AGENTS}, volume={41}, ISSN={["1879-291X"]}, DOI={10.1016/j.ultrasmedbio.2014.10.020}, abstractNote={Many studies have explored phase-change contrast agents (PCCAs) that can be vaporized by an ultrasonic pulse to form microbubbles for ultrasound imaging and therapy. However, few investigations have been published on the utility and characteristics of PCCAs as contrast agents in vivo. In this study, we examine the properties of low-boiling-point nanoscale PCCAs evaluated in vivo and compare data with those for conventional microbubbles with respect to contrast generation and circulation properties. To do this, we develop a custom pulse sequence to vaporize and image PCCAs using the Verasonics research platform and a clinical array transducer. Results indicate that droplets can produce contrast enhancement similar to that of microbubbles (7.29 to 18.24 dB over baseline, depending on formulation) and can be designed to circulate for as much as 3.3 times longer than microbubbles. This study also reports for the first time the ability to capture contrast washout kinetics of the target organ as a measure of vascular perfusion.}, number={3}, journal={ULTRASOUND IN MEDICINE AND BIOLOGY}, author={Sheeran, Paul S. and Rojas, Juan D. and Puett, Connor and Hjelmquist, Jordan and Arena, Christopher B. and Dayton, Paul A.}, year={2015}, month={Mar}, pages={814–831} }
 @article{sheeran_rojas_puett_hjelmquist_arena_dayton_2014, title={In Vivo Quantification of Image Enhancement and Circulation Kinetics for Phase Change Perfluorocarbon Agents Using Custom Pulse Sequences}, ISSN={["1948-5719"]}, DOI={10.1109/ultsym.2014.0103}, abstractNote={Few investigations have been published demonstrating the in vivo contrast characteristics of phase-change perfluorocarbon droplets. In this study, we examine the properties of low boiling point nanoscale droplets compared to microbubbles with respect to image enhancement and circulation time. To accomplish this, we develop a custom pulse sequence to vaporize and image droplets using the Verasonics research platform. Results show that droplets can produce similar contrast compared to microbubbles, and can circulate for significantly longer than microbubbles, depending on formulation. Finally, this study demonstrates a novel concept in contrast-enhanced ultrasound: capture of droplet-generated contrast wash-out in the target organ.}, journal={2014 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS)}, author={Sheeran, Paul S. and Rojas, Juan D. and Puett, Connor and Hjelmquist, Jordan and Arena, Christopher B. and Dayton, Paul A.}, year={2014}, pages={417–420} }