New Imaging Methods May Aid Dx of Barrett's

Source Courtesy Dr. Prateek Sharma

NBI accurately detects the dysplastic tissue seen in Barrett's esophagus.

White light endoscopy relies on random tissue biopsy to detect Barrett's.

Autofluorescent imaging has a high false-positive rate for Barrett's tissue.

Confocal endomicroscopy may be useful as an adjunct to NBI.

Source Images courtesy Dr. Prateek Sharma

Autofluorescence and Confocal Imaging

Autofluorescence imaging is a “broad-based imaging tool” that can monitor changes in the pattern of distribution of autofluorescent proteins in the esophagus when normal mucosal tissue becomes dysplastic or cancerous, Dr. Prateek Sharma explained.

Tissue patches that are found to be dysplastic or cancerous could then be targeted for biopsy. However, research suggests that autofluorescence imaging may have a false-positive rate that is too high to be useful as a stand-alone screening and surveillance procedure for Barrett's esophagus because tissue patches that have been flagged as dysplastic or cancerous may be normal or inflamed tissue.

In another study presented at Digestive Diseases Week by Dr. Sharma's research group, autofluorescence imaging conducted with a prototype multimodality endoscope from Olympus America Inc. had poorer sensitivity for detecting high-grade dysplasia or cancer than did narrow band imaging (NBI) in 25 patients who were undergoing surveillance of Barrett's or endoscopic treatment of high-grade dysplasia or cancer. Autofluorescence imaging detected a total of 23 abnormal areas in 11 patients, whereas NBI located 19 abnormal areas in 12 patients.

“The jury is still out on autofluorescence, and we still need further studies to define its exact role,” he said.

The broad-based technique of NBI or autofluorescence imaging also might be combined with a third, much more focused technique called confocal endomicroscopy, which is a “way of doing in vivo histology,” Dr. Sharma said.

In areas of tissue that already have been highlighted as abnormal with NBI or autofluorescence imaging, this method could take a micrometer-level view of irregularities in glands, increases in cell sizes, and changes in the entire arrangement of cells. However, no study has yet been published that combines confocal endomicroscopy with another technique.