To diagnose illness in areas of the body that are hard-to-reach, clinicians increasingly use tiny space age probes, which can see inside single living cells. A new study published in the journal Digestive Diseases and Sciences reveals that specialists who are beginning to use these devices may be interpreting what they see in different ways.

Dr. Michel Kahaleh, chief of endoscopy at the Center for Advanced Digestive Care at NewYork-Presbyterian/Weill Cornell and professor of clinical medicine at Weill Cornell Medical College, frequently uses a tiny microscope in the narrow bile ducts that connect the liver to the small intestine to check for cancer and also uses it for minute exploration of the pancreatic duct.

Kahaleh is one of a few doctors in the country who is experienced in using this type of technology and due to the novelty of these devices, he suspected that specialists who are starting to use this technology might interpret what they see in different ways.

His suspection was confirmed after sending 6 different specialists at 5 different medical institutions recorded videos, which featured probe-based confocal laser endomicroscopy (pCLE) deep inside 25 patients with abnormally narrowed bile ducts. Regardless of whether the 6 participating specialists saw cancer, a simple inflammation or a benign condition in the video, Kahaleh and his team found their agreement on the clinical importance of what they saw as “poor” to “fair”.

Dr. Kahaleh, who is also medical director of the Pancreas Program at Weill Cornell, explains:

“That means physicians need to come up with a standard way of interpreting what the videos reveal in order to properly use this “amazing technology. We can see detail that was just unimaginable a decade ago–this breakthrough is born for the bile duct and those tiny tubes and complicated organ structures that no one has ever been able to visualize before. And when physicians are certain of what they are seeing, we will be able to greatly improve patient treatment, avoiding unnecessary surgery whenever possible.”

To help in the process of digestion, the human bile duct transports bile secreted by the liver to the small intestine. However, certain conditions, such as inflammatory disease, the passing of gallstones or a tumor can constrict the bile duct, which in turn results in a blockage that can lead to jaundice, cirrhosis, and other conditions.

Two years ago, the U.S. Food and Drug Administration approved pCLE diagnostic systems, i.e. a mini microscopic probe that is threaded inside a larger “spy glass” probe, for use in the bile duct and pancreas. The pCLE can record images of blood vessels, mucosal structures and epithelial tissue in real-time, and display them on a large monitor so that they can be examined by the physicians.

Kahaleh says that the majority of institutions potentially still apply a rather ‘hit-or-miss’ technique to identify cancer in bile ducts. The standard technique is to thread a probe inside the duct to where it is abnormally narrowed and then using a small brush or tiny forceps to gather some cells that can subsequently be biopsied in a lab. But Kahaleh stresses: “But we still miss 20-30 percent of bile duct cancer or other tumors in this way, and that is unacceptable.”

It is possible to remove a tumor in the bile duct and make a replacement out of the bowel. Kahaleh remarks: “It’s a big operation, and you want to make sure it is necessary. If there is any way to prevent surgery that would be a phenomenal advance for patient care.”

For their study, Kahaleh and his team asked 6 gastroenterologists trained in using bile duct pCLE to analyze seven variables seen in the 30-second to 1-minute video clips, and to subsequently make a diagnosis of whether or not the bile duct was cancerous. The only person who knew the results in advance was the study coordinator. The results were confirmed from tissue biopsies taken after surgery, or other evidence of malignancy. Depending on the variable and also for the final diagnosis, the team discovered a poor to fair agreement on the diagnosis amongst the specialists.

Dr. Kahaleh concludes:

“It is clear physicians need a standard by which to understand what they see, which will also need to involve more training. This is increasingly important, as these minimally invasive systems are proposed for use in diagnosing other health issues in the gastrointestinal tract, including ulcerative colitis and Barrett’s esophagus. We can now see inside these tiny organs, but we just need to know exactly what we are looking at.”

Written by Grace Rattue