An estimated 120 million people worldwide are infected with lymphatic filariasis, a parasitic, mosquito-borne disease that can cause major swelling and deformity of the legs, a condition known as elephantiasis. Health-care workers rely on leg measurements to assess the severity of the condition. However, measuring legs that are severely swollen often proves cumbersome and impractical.

But now, scientists at Washington University School of Medicine in St. Louis, working with collaborators in Sri Lanka, have shown that a portable scanning device can measure limb enlargement and disfigurement faster and more easily in patients with elephantiasis. The research tool makes it easy to obtain accurate measurements and determine whether treatments to reduce swelling are effective.

The study is published online Oct. 16 in The American Journal of Tropical Medicine and Hygiene.
"This is important because it will allow doctors and researchers to take very accurate limb measurements in developing nations, where there are often limited tools to monitor swollen limbs," said senior author Philip J. Budge, MD, PhD, an assistant professor of medicine in the Division of Infectious Diseases at Washington University.

In patients with elephantiasis, the parasitic worms that cause the disease make their way into the lymphatic system and prevent the lymph vessels from working properly, which leads to swollen legs. This condition also is referred to as lymphedema.

"Unfortunately, the medication does not usually reverse lymphedema in those already affected," Budge said. "The ability to get these measurements rapidly will make it much easier to treat patients, including those in clinical trials exploring better treatment therapies."

The device is essentially an infrared sensor, mounted on an iPad, that produces a highly accurate, virtual 3-D reconstruction of the legs using scanning technology similar to that found in Microsoft's Xbox Kinect video game system. It was created by Atlanta-based startup LymphaTech to measure lymphedema that sometimes develops in cancer patients after lymph nodes are removed during surgery.

After learning about the technology, Washington University researchers Budge and Ramakrishna Rao, PhD, an associate professor of medicine, teamed up with international partners to test the device on 52 patients with varying stages of lymphedema at a clinic in Galle, Sri Lanka. Working with physicians at the clinic, the team compared scanner results with results from two other techniques frequently used to ascertain the severity of elephantiasis: use of a tape measure, and water displacement.

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