UD researchers study microbubbles used in diagnostic ultrasound
Pictured are, from left, engineering graduate students Shirshendu Paul and Amit Katiyar, Kausik Sarkar, associate professor of mechanical engineering, and undergraduate researcher Daniel Russakow.


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12:11 p.m., July 20, 2010----A University of Delaware research team has received a $300,000 National Science Foundation grant to better understand ultrasound echoes of encapsulated microbubbles used for noninvasive blood pressure monitoring.

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Ultrasound, which uses a pulsing high frequency sound beyond the upper limit of human hearing to peer into the body and provide images, is an important tool in modern health care.

Kausik Sarkar, associate professor in the Department of Mechanical Engineering, is the principal investigator for the project.

Sarkar said microbubbles -- tiny encapsulated bubbles of gas -- are used as a contrast-enhancing agent for diagnostic ultrasound because they are small enough to penetrate deep into the human body.

The project is predicated on the use of a subharmonic signal -- a signal at a frequency lower than that of the exciting ultrasound pulse -- from these microbubbles to noninvasively quantify and monitor the ambient blood pressure in an organ.

“Local ambient blood pressure provides important information regarding the functional integrity of many organs, and it can be used to diagnose and monitor many diseases such as defective heart valves, malignant tumors and portal hypertension,” Sarkar said. “We propose to use in vitro experiments, modeling, perturbative analysis and numerical simulation to investigate the dynamics of contrast microbubbles with a view to understand and optimize such applications.”

Optimization is important because while ultrasound is the safest means of medical imaging, its utility is limited by poor contrast, Sarkar said, noting that about 20 percent of the 20 million echocardiographies performed each year in the United States do not provide definitive diagnosis for coronary heart disease.

“A good contrast agent can measurably improve ultrasound imaging,” he said, and better understanding the response of contrast microbubbles is key to that improvement.

Sarkar's research group has been working on encapsulated contrast microbubbles for a number of years and has established a collaborative research program with Thomas Jefferson University's radiology department that has secured funding from Department of Defense and the National Institutes of Health.

The UD team had a prior NSF grant and also is funded by an NIH IDeA Network of Biomedical Research Excellence (INBRE) grant.

Sarkar joined the UD faculty in 2001. He received a bachelor's degree from the Indian Institute of Technology, and a master's and doctorate from the Johns Hopkins University.

Article by Neil Thomas
Photo by Kathy F. Atkinson