Bernarda Viteri, MD, was a clinical research assistant at Children’s National Health System in Washington, DC, when she became interested in kidney imaging. She was intrigued by the ability to visualize kidney function and the information images can provide that more traditional methods like a blood test or urinalysis can’t.
Then, during her fellowship in pediatric nephrology at Mount Sinai Hospital, she attended a workshop presented by the Center for Pediatric Contrast Ultrasound at Children’s Hospital of Philadelphia. Contrast-enhanced ultrasound (CEUS) uses a contrast agent to improve the image quality of an ultrasound scan. The contrast agent is made of tiny, gas-filled microbubbles that enhance the image, which leads to easier, faster, and more accurate diagnostic results.
One of the most important aspects of contrast ultrasound is that it is safe, since it does not use any radiation, and is non-nephrotoxic. Additionally, it is more comfortable for pediatric patients than other imaging modalities since it can be performed at the bedside. Contrast-enhanced ultrasound in children has been used in Europe since the late 1990s. It was only recently approved for use in children by the U.S. Food and Drug Administration (FDA) for specific indications of the heart, liver and urinary system when suspected of known vesicoureteral reflux.
Benefits of contrast-enhanced ultrasound in kidney transplant patients
Viteri saw the benefits of contrast-enhanced ultrasound for children who have undergone kidney transplantation. After the workshop, she connected with Kassa Darge, MD, PhD, founder of the Center for Pediatric Contrast Ultrasound and workshop leader. That connection led her to CHOP, where she recently took a position as an attending nephrologist and began a two-year master’s degree in translational research with a focus on kidney imaging at the University of Pennsylvania.
Kidney transplantation is the treatment of choice for children with end-stage kidney disease (ESKD). Compared to dialysis, kidney transplant offers improved health, quality of life and survival. Currently, the gold standard for diagnosis of transplant rejection is a biopsy of the transplant kidney, an invasive procedure that can lead to bleeding, development of renal arteriovenous fistulas, and sampling differences that may not reflect the entire kidney. On the other hand, CEUS provides dynamic information, such as perfusion of the entire kidney being evaluated (qualitative and quantitative data); it is cost-effective and noninvasive, with no risk of bleeding or arteriovenous fistulas forming; and it has the potential of serving as a screening tool of vascular rejection.
Through her master’s program, Viteri is currently collaborating with researchers at Penn to further study CEUS in pediatric kidney transplantation to establish CEUS as a standard-of-care practice in this population.
Noninvasive imaging for patients with obstructive urinary tract dilation
Viteri is also working to identify quantitative imaging biomarkers of adverse renal outcomes in patients with obstructive urinary tract dilation (UTD), previously known as hydronephrosis, using noninvasive imaging. The most common imaging modalities utilized to assess obstruction in the United States (after ultrasound has shown UTD) are MAG3 renal scan and magnetic resonance urography (MRU). These provide several specific objective quantitative measurements that assist in the interpretation of an obstructive urinary system. MRU is an innovative and radiation-sparing imaging modality that is superior in defining a detailed anatomy of the kidney and urinary tract when compared to MAG3 renal scan.
Viteri is currently planning a large retrospective cohort study focused on defining MRU parameters such as the pediatric age normal range of the specific quantitative measurements and curves of MRU studies. Identification of critical imaging biomarkers of ureteropelvic junction obstruction will allow her team to develop a model of parameters that predict adverse effects on renal function, blood pressure, and kidney growth and size.