Many clinicians are well familiarized with standard contrast agents such as barium and iodinated compounds to enhance angiographic imaging. Ultrasound, capable of visualizing bloodflow with the use of doppler alone, is yet insufficiently sensitive to capture perfusion of organs and/or tumors at the capillary level. What special kinds of contrast enhancements are needed for ultrasound in this case? Dr. Stephanie Wilson, professor of medical imaging and obstetrics and gynecology at the University of Calgary in Alberta, Canada, discusses the science and art of using micro-bubble contrast agents, and the emergence of contrast-enhanced ultrasound (CEUS) as a safer alternative to traditional angiography. Dr. Jason Birnholz hosts.