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CLINICAL DISCUSSION Detecting One of Diabetes' Most Harmful Complications With DDOT A NONINVASIVE, LIGHT-BASED IMAGING MODALITY DEVELOPED BY RESEARCHERS AT COLUMBIA UNIVERSITY MAY ONE DAY ALLOW CLINICIANS TO DIAGNOSE AND MONITOR PERIPHERAL ARTERY DISEASE (PAD) IN INDIVIDUALS WITH DIABETES MORE ACCURATELY. C U R R E N T LY, exists in clinicians' a bi l it y t o detect and monitor PAD in individuals with diabetes, thanks to a combination of flaws and contraindications from diagnostic methods. Ankle brachial index (ABI) and lower-limb duplex-ultrasound, for example, do not reveal a full picture of blood flow in the extremities in some cases, while computed tomography angiography and magnetic resonance angiography may be unsafe for individuals with renal insufficiency, as these imaging modalities use potentially nephrotoxic contrast agents. A new technique — dynamic diffuse optical tomography (DDOT) — may give clinicians the clearest pictures yet of the quality of blood flow in patients' extremities by obtaining a direct measure of distal perfusion rather than the surrogate ones yielded by the aforementioned modalities. A GAP A New Method of Measurement DDOT uses a dynamic near-infrared optical tomography imager to send light through optical fibers into the tissue of the foot via a measuring probe placed around the foot. The process — which uses multiple wavelengths to gather information — produces images that reveal where oxy- and deoxy-hemoglobin are concentrated; this information is also used to determine total hemoglobin concentration. In a study recently published in the Optical Society journal Biomedical Optics Express, researchers at Columbia University used a five-stage protocol to perform DDOT on a healthy individual, an individual with PAD and an individual with PAD and diabetes. According to the researchers, it was possible to distinguish between a healthy patient and a PAD patient with ABI. However, ABI did not allow them to distinguish between 14 | Austin MD NEWS I MDNEWS.COM the individual with PAD and diabetes and the others. Clinicians performed the protocol three times with each patient in the following steps: + one-minute baseline measurement + inflation of a pressure cuff around the thigh to 60 mmHg for one minute to allow blood to accumulate in the foot + one-minute recovery of the foot + inflation of the pressure cuff to 120 mmHg to allow blood to pool in the foot again + second recovery period for the foot During DDOT, detectors measured the amount of light passing through the tissue of the foot while the cuffs were activated. The more blood in the tissue, the less light was detected. Greater percentage drops in detector intensity in the healthy patient revealed that more blood accumulated in the foot of the healthy individual than in the feet of the patients with narrow arteries. Image sequences revealed it took longer for blood to pool in the feet of the individuals with PAD, and the blood level of the individual with diabetes and PAD did not completely return to baseline when the cuff was released, indicating plaque build-up in vessels. Researchers concluded DDOT is better suited than other modalities to detect arterial plaque accumulation because during the study, it was able to identify differences in blood flow between all three patients. This research suggests DDOT may be an important diagnostic and monitoring tool for clinicians in the future. I A DV E R T I S E R S ' I N D E X aha Digital Marketing + Creative ................................................... 11 Brown McCarroll ...................................................................................5 Danemiller ............................................................................................ 13 LIVESTRONG .......................................................Inside Front Cover Padgett Stratemann............................................................................5 Broadway Bank ................................................................Back Cover

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