New technique provides detailed internal surface biopsies
A new optical imaging technique has been developed that can provide three-dimensional microscopic views of the inner surfaces of blood vessels and gastrointestinal organs, according to a new report in the journal Nature Medicine. The technique — which uses optical frequency-domain imaging (OFDI) to visualize broad areas of (in the case of the study) the esophagus and coronary arteries of living pigs — was developed at the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH).  According to the report, the technique is an advance over optical coherence tomography (OCT), which is another noninvasive MGH-developed technology that details much smaller areas.

"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," said 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."

OFDI is able to look at over 1,000 points simultaneously by using a new type of laser created by the research team. The device’s fiber optic catheter probe allows for rapid acquisition of the data required to create the detailed microscopic images.

The report authors report that OFDI was successfully used to image 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, producing three-dimensional microscopic images of the surfaces of segments 24 to 63 millimeters long. The technique is also able to differentiate between healthy and damaged tissue.

Potential applications for OFDI include the diagnosis of Barrett's esophagus, a precursor to esophageal cancer. Another possible major application would be examining coronary arteries for the vulnerable plaques considered highly likely to provoke heart attacks.