Ultrasound experts at this week's Advances in Contrast Ultrasound International Bubble Conference in Chicago called for expanded use of ultrasound contrast agents to offer patients broader access to what they said was low-cost, safe, and reliable diagnostic imaging.
Ultrasound contrast agents are biocompatible and injected during an ultrasound scan to enhance the resolution of an ultrasound image. They contain microscopic gas-filled microbubbles that reflect ultrasound signals as they flow through the body's circulation and are expelled from the body within minutes after injection, according to speakers at the conference.
But uptake of ultrasound contrast has been slower than expected, especially in the U.S. Some industry experts believe this slow adoption could be due to warnings that have been issued by the U.S. Food and Drug Administration (FDA) pertaining to their use.
For example, the FDA earlier in 2021 added a contraindication against the use of ultrasound contrast in patients with allergies to polyethylene glycol. Over a dozen cases of adverse reactions are believed to have occurred.
Proponents of ultrasound contrast have also requested that the FDA remove a black-box warning added to contrast packaging in 2007 after reports of 11 deaths that occurred between 2001 and 2007 following contrast use. These experts believe that follow-up studies performed since those incidents have confirmed the safety of ultrasound contrast.
At this week's conference, ultrasound experts reemphasized the safety of ultrasound contrast agents, pointing out that they contain no dye and present no known risk of liver or kidney damage. Patient sedation is also not required.
Dr. Stephanie Wilson from the University of Calgary said ultrasound contrast agents are versatile and useful for imaging tumors and organ systems throughout the body, including the kidney, bowel, breast, pancreas, prostate, and carotid arteries.
Dr. Richard Barr, PhD, from Northeast Ohio Medical University, who also spoke at this week's event, said doctors are increasingly using ultrasound agents for unapproved uses and professional guidelines now support these additional indications.
Barr, who is also editor in chief of the Journal of Ultrasound in Medicine, noted that doctors are now reimbursed for unapproved "off-label" uses of ultrasound contrast agents.
Experts touted contrast-enhanced ultrasound contrast-enhanced ultrasound as highly effective for monitoring patient response to therapy. They also said the radiation-free imaging technique is often equivalent or superior to more expensive imaging tools like MRI or CT.
Dr. Thomas Porter from the University of Nebraska Medical Center added that cardiac imaging would also benefit from more holistic regulation and approval of these agents. He said contrast-enhanced ultrasound can play a pivotal role in accurately diagnosing cardiovascular disease.
Panelists called on the FDA to work with agent manufacturers on expanding approved uses of ultrasound contrast agents for whole-body imaging, saying limited regulatory approvals restrict opportunities for education and training, as well as patient access.
Experts also said approved uses would expand labeling information and instructions for optimal use.
