Scanner on a String

A pill-sized endomicroscopy capsule on a flexible tether has been shown in early clinical tests to quickly gather complete 3D microscopic images of the esophagus. The work offers potential for a reusable, inexpensive, and easily employed device that could allow early detection of Barrett esophagus and other conditions (Nat Med 2013;19:238–40).

“This is a potential game-changer for diagnosing diseases of the esophagus,” says Gary Tearney, MD, PhD, senior author of the article, professor of pathology at Harvard Medical School, and associate director of the Massachusetts General Hospital Wellman Center for Photomedicine in Boston.

Most surprisingly, Tearney says, human testing gave a proof of concept that when a patient swallows the optical capsule the esophagus grabs the capsule and moves it down smoothly, allowing detailed imaging of the entire organ. “We didn't try this technique for a long time because we didn't think it would work,” he remarks.

After a patient swallows the endomicroscopy capsule, the device can be controlled in the esophagus by manipulation of a plastic ball attached to a flexible tether. The capsule could potentially make esophageal screenings less expensive and more widely performed.

The 25-mm-long, 13-mm-diameter capsule includes an optical coherent tomography imaging system with a revolving infrared laser scanner, which gathers complete 3D images of the esophageal wall, including data on subsurface structures. In a study of 6 patients with Barrett esophagus (a precancerous condition) and 7 healthy volunteers, the entire esophagus could be imaged successfully in 4 passes—2 down the organ and 2 up—in about 6 minutes. In contrast, conventional endoscopy may take about 90 minutes and does not yield a complete microscopic image of the esophagus.

The capsule device can be sanitized for reuse and promises to be far less expensive than either traditional endoscopy or untethered endoscopy capsules, Tearney says. The tethered capsule could require relatively little operator training and could work in almost any health care setting, with the patient simply swallowing the capsule.

By American Cancer Society estimates, more than 15,000 people in the United States died of esophageal cancer in 2012. “In other areas of the world, squamous cell cancer of the esophagus is very significant,” Tearney adds. “Our hope is that these capsules can be adopted widely, opening up the possibility of screening much larger populations for gastrointestinal tract disease.”