June 13, 2017
During her recent elective in pediatric radiology, pediatric resident Suzanne Al-Hamad learned about a new imaging modality in this country for children called contrast enhanced ultrasound, or CEUS, that offers similar diagnostic capability of CT and MRI without the risk of radiation exposure with CT or the need for sedation with MRI. After hearing a lecture on CEUS by pediatric radiologist Misun Hwang, you would have thought she had discovered a hidden treasure. But it was one she wanted to share with others—so much so that she presented on contrast ultrasound at Johns Hopkins Children’s Center grand rounds.
“Dr. Hwang had so many ideas for all of the uses of contrast ultrasound but she needed some help getting the word out,” says Al-Hamad. “I was excited to take on that challenge.”
CEUS, Hwang explains, has been used in Europe for the last two decades. The U.S. Food and Drug Administration approved its usage for evaluation of liver and vesicoureteral reflux in pediatric patients in 2016. Since then, academic medical centers have been expanding its clinical applications to include trauma, inflammatory bowel disease, tumor, neonatal hypoxic ischemic injury, and necrotizing enterocolitis.
In evaluating these conditions, the benefit of CEUS over conventional ultrasound is its high-resolution visualization of blood perfusion into vital organs through the use of contrast agents containing gas-filled microbubbles that have a high degree of echogenicity—the ability to reflect ultrasound waves. Compared with conventional grade-scale ultrasound, the spatial resolution of contrast ultrasound is much better, explains Hwang, especially for neonates with hypoxic ischemic injury, one of her special clinical and research interests.
“If a neonate has hypoxic ischemic injury and multiple infarcts, the grade scale ultrasound may not show it readily, while contrast gives you more functional information,” says Hwang. “You’re not looking at black and white—you’re looking at real time perfusion data, which is quantifiable.”
Adds Al-Hamad, “With conventional ultrasound, to the untrained eye you don’t know what’s behind and what’s in front. With contrast ultrasound and the vascularity highlighted, you can much more easily differentiate spatial resolution or where things are relative to each other.”
In addition to no radiation exposure or risk of kidney damage from the contrast agent—important considerations especially for pediatric patients—another benefit of CEUS is its portability as a first-line imaging modality in many clinical settings, including the bedside, outpatient clinic or ED. Hwang notes that the modality is especially useful when imaging critically ill neonates hooked up to various lines.
“Transport to an MR suite is a challenge for neonates, especially when there are very ill,” says Hwang. “The whole process is very cumbersome for expedited care.”
The only downside? CEUS does require an IV.