A gullet-scanner the size of a pill

Medical Imaging

Researchers have developed an imaging system enclosed in a capsule about the size of a multivitamin that takes detailed, microscopic images of the oesophagus. The system has many advantages over traditional endoscopy and doctors may soon have a new way to screen patients for Barrett’s oesophagus – a precancerous condition usually caused by chronic exposure to stomach acid.

“This system gives us a convenient way to screen for Barrett’s that doesn’t require patient sedation, a specialized setting and equipment, or a physician who has been trained in endoscopy,” said Professor Gary Tearney who developed the system with his colleagues at the Wellman Centre and MGH Pathology Department and the corresponding author of the study, published in Nature Medicine.

The capsule contains an optical frequency domain imaging (OFDI) technology. This is a laser tip which rapidly rotates while emitting a beam of near-infrared light and sensors that record light reflected back from the oesophageal lining. The capsule is also attached to a string-like tether which connects it to the imaging console allowing the health professional to control the system.

After the patient has swallowed the capsule, it is carried down the oesophagus by normal contraction of the surrounding muscles. OFDI images are taken throughout this transit. When the capsule reaches the stomach, it can be pulled back up by the tether.

To test the system, 13 patients were enrolled on the trial; six of whom were known to have Barrett’s oesophagus. The physicians were able to image the entire oesophagus in less than a minute, and a procedure involving four passes could be completed in around six minutes.

The researchers say that the detailed microscopic images produced by the OFDI system can reveal subsurface structures not easily seen with endoscopy and clearly distinguished the cellular changes that signify Barrett’s Oesophagus. Additionally, study patients who had previously undergone tradition endoscopy said they preferred this new procedure.

“The images produced have been some of the best we have seen of the oesophagus,” said Tearney. “We were originally concerned that we might miss a lot of data because of the small size of the capsule, but were surprised to find that one that pill has been swallowed, it is firmly ‘grasped’ by the oesophagus, allowing complete microscopic imaging of the entire wall.”

Tethered capsule endomicroscopy enables less invasive imaging of gastrointestinal tract microstructure http://www.nature.com/nm/journal/vaop/ncurrent/abs/nm.3052.html