Research Aimed at Improving Medical Imaging of Leg Ulcers

Jun Xia, PhD, associate professor of biomedical engineering, has received a $1.6 million grant to improve medical imaging for people with chronic leg ulcers. The project is a collaboration with the surgery clinic of UBMD Physicians’ Group and other UB researchers.

The Department of Biomedical Engineering is a joint program between the Jacobs School of Medicine and Biomedical Sciences and UB’s School of Engineering and Applied Sciences.

“Chronic leg ulcers are basically a wound on the leg that doesn’t heal,” says Xia, the principal investigator whose research focuses on developing new optical and ultrasonic imaging techniques for use in cancer, vascular and neurological research and treatments.

“It takes a long time to heal — several months, or years, or it never heals,” he says. “The reason is there is poor blood perfusion to the tissue, which means the blood cannot reach the portion of the injured tissue. If you cut off the blood supply, the tissue will eventually die, and that is why chronic ulcers may lead to poor health outcomes.”

Chronic leg ulcers affect more than 500,000 Americans each year, according to the Cleveland Clinic. They lead to costly treatments, reduced mobility and quality of life, and increased risk of death.

Restoring proper blood flow to the wounded area after surgery is key to effective medical treatment, planning and monitoring. To do that, extensive, efficient medical imaging is needed to properly visualize what is happening around the ulcer.

However, current methods, which include X-rays, MRIs and ultrasound, have limitations in evaluating small vessels, which weakens their effectiveness in monitoring blood perfusion to the ulcer.

The four-year research project is focused on finding a noninvasive, accurate imaging tool to assess post-surgical circulation.

“Right now, there’s no effective technique to identify whether the blood perfusion has been restored after the surgery,” Xia says.

The technique Xia’s developing uses photoacoustic tomography to produce effective imaging. A near-infrared light irradiates the affected area and heats the blood. The blood cells then expand slightly, a process that generates sound waves.

An ultrasound machine, which uses sound waves to create imaging, perceives the heat-generated sound waves and translates them into visual imaging. Blood, as a light absorber, is a great generator for sound, which is why the imaging shows the distribution of blood in the affected area, as well as whether proper perfusion of blood has been restored.

In addition to the grant provided by the National Institute of Biomedical Imaging and Bioengineering, the research project has gained support from vascular clinics at Buffalo General Medical Center and the Erie County Medical Center. The researchers have obtained preliminary data with support from UB’s Clinical and Translational Science Institute.

“Our idea is, after the UBMD vascular surgery team has done the surgery to restore proper blood flow, we’ll do the imaging,” Xia says. “We’ll compare the results with the imaging acquired before the surgery to see if there is any change in the blood perfusion to the ulcer. If there is a positive change, then we know the surgery was successful.”

Currently, surgeons are restrained by the lack of imaging techniques to assess distal perfusion. As a result, they end up waiting a few months to see whether blood flow has been restored. Xia wants to bring that wait time to two weeks or less.

“This will allow surgeons to identify earlier than current imaging techniques whether the surgery was successful,” he says.

Additional investigators from the Jacobs School are:

• Linda M. Harris, MD, professor of surgery and director of the vascular surgery integrated residency and vascular surgery fellowship programs
• Sikandar Z. Khan, MD, clinical assistant professor of surgery

Other UB investigators are:

• Praveen Ravindra Arany, DDS, PhD, assistant professor of oral biology in the School of Dental Medicine
• Wenyao Xu, PhD, associate professor of computer science and engineering in the School of Engineering and Applied Sciences
• Guan Yu, PhD, assistant professor of biostatistics in the School of Public Health and Health Professions