New Technique to Detect Narrowing of Arteries in Diabetes Patients

The new study that is carried in the journal Biomedical Optics Express explains how to diagnose and monitor one of the most serious complications of diabetes known as the Peripheral Arterial Disease (PAD).

PAD is the narrowing of arteries that is triggered due to plaque accumulation and in the vascular walls, frequently resulting in insufficient blood flow to the body. As the disease progresses, this distance becomes shorter, and in later stages the pain becomes severe. Thereby increasing the chances of heart attacks and strokes.

The new noninvasive imaging technique known as dynamic diffuse optical tomography imaging (DDOT), uses near infrared light to map the concentration of hemoglobin in the body's tissue. This mapping will detect the flow of blood in the hand and legs.

"Currently, there are no good methods to assess and monitor PAD in diabetic patients," explains Andreas Hielscher, Ph.D., professor of Biomedical and Electrical Engineering and Radiology, and director of the Biophotonics and Optical Radiology Laboratory at Columbia University.

"Patients with PAD experience foot pain, called 'claudication,' while walking," adds Gautam Shrikhande, M.D., assistant professor of surgery, and director of the Vascular Laboratory at Columbia's Medical Center. "This pain continues, even at rest, as the disease progresses. In more advanced stages, PAD patients develop sores or ulcers that won't heal. Then, cell death, a.k.a. 'gangrene,' occurs and amputation is often the only solution. It's extremely important to diagnose PAD early, because medication and lifestyle changes can alleviate the disease."

"We've successfully used DDOT to detect PAD in the lower extremities," says Michael Khalil, a Ph.D. candidate working with Hielscher at Columbia. "One key reason why DDOT shows so much promise as a diagnostic and monitoring tool is that, unlike other methods, it can provide maps of oxy, deoxy and total hemoglobin concentration throughout the foot and identify problematic regions that require intervention."

"Using instrumentation for fast image acquisition lets us observe blood volume over time in response to stimulus such as a pressure cuff occlusion or blockage," said Hielscher.

This device can be used to monitor the presence of haemoglobin. Red and near infra red light is reflected at different angles in the areas that are susceptible to arterial disease. These specific wavelengths of light are then absorbed or scattered, depending on the concentration of hemoglobin.

"In the case of tissue, light is absorbed by hemoglobin. Since hemoglobin is the main protein in blood, we can image blood concentrations within the foot without using a contrast agent," Hielscher points out.

In the United States nearly 25 million people are victims of diabetes. This tool is simple to identify and monitor diabetics with PAD.