"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 optical coherence tomography (OCT), is clearly not sufficient," says Brett Bouma, PhD, of the Massachusetts General Hospital (MGH) -Wellman Center, the report's senior author. "With optical frequency-domain imaging (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.

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, producing three-dimensional microscopic images of the surfaces of segments 24 to 63 millimeters long.

Among potential applications for OFDI could be diagnosis of Barrett's esophagus, a precursor to esophageal cancer that can be identified with OCT, provided the affected tissue is scanned. The researchers estimate that the esophageal scan conducted in this study could be reduced from 6 minutes to less than 1 with more powerful computer processing.

MEDICA.de; Source: Massachusetts General Hospital