A new optical imaging technique, developed at the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH), can provide three-dimensional microscopic views of the inner surfaces of blood vessels and gastrointestinal organs. In their report in the journal Nature Medicine, receiving early online release today, the MGH-Wellman researchers describe using optical frequency-domain imaging (OFDI) to visualize broad areas of the esophagus and coronary arteries of living pigs. The technique is an advance over optical coherence tomography (OCT) another noninvasive MGH-developed technology that details much smaller areas and could be useful for identifying precancerous lesions and dangerous deposits of plaque in the coronary arteries.
"For diagnosing early-stage disease, the clinician has been basically looking for a needle in a haystack; so sampling only a few microscopic points of an organ, as we could with OCT, is clearly not sufficient," says Brett Bouma, PhD, of the MGH-Wellman Center, the report's senior author. "With OFDI, we can now perform microscopy throughout very large volumes of tissue without missing any locations."
While OCT can examine surfaces one point at a time, OFDI is able to look at over 1,000 points simultaneously by using a new type of laser developed at MGH-Wellman. Inside the fiberoptic catheter probe, a constantly rotating laser tip emits a light beam with an ever-changing wavelength. Measuring how each wavelength is reflected back, as the probe moves through the structure to be imaged, allows rapid acquisition of the data required to create the detailed microscopic images.
In the Nature Medicine paper, the MGH-Wellman team reports that OFDI successfully imaged the inner esophageal surfaces of living pigs, revealing the structural details and vascular networks of 4.5-centimeter-long segments with less than 6 minutes scanning time. Scans of coronary artery surfaces were similarly successful,
Contact: Sue McGreevey
Massachusetts General Hospital