“No bowel prep,” “no I.V.,” “no discomfort or complications,” “improved accuracy,” and “no more colonoscopy” are a few of the exclamations being made by the press and public regarding capsule endoscopy. Does it measure up to these claims?

Wireless capsule endoscopy is now available. The system miniaturizes technologies into a capsule containing a light source, image sensor, transmitter, and power source (battery). The pill is large, at 11 x 28 mm, but swallowable by most patients. As the capsule travels through the GI tract, it takes two pictures per second, sending images to a computer. The signal is received by an array of sensors that are attached by a special belt to the abdomen. The sensors are connected to a portable computer worn on the belt, similar to a Holter monitor used for monitoring cardiac rhythm. Peristalsis moves the capsule through its journey during which time the patient carries on a “normal” day. After 8 hours, the sensors, belt, and computer are removed. The information is downloaded into a desktop or laptop computer for processing and viewing the pictures. The images obtained are high quality with resolution that is impressive. There are no controls to steer, slow down or speed up the capsule during passage, thus a small lesion may be missed or seen only on a few images if the capsule is traveling rapidly at that time.

The capsule is designed for imaging the small bowel. It does not image the colon at this time. Other current techniques to evaluate the small bowel have limitations. Endoscopically, a pediatric colonoscope can be used to reach the distal duodenum and most proximal jejunum (first parts of the small bowel). A fiberoptic enteroscope, a special longer scope available in Cincinnati at Christ Hospital, can probe considerably deeper into the small intestine but still sees only about half of the approximately 20 feet of it. Advantages of scope techniques are control and the ability to biopsy and cauterize lesions. Radiographically, the small bowel can be imaged by drinking the barium (small bowel follow through) or infused via tube (enteroclysis). Flat or small lesions are difficult to see. Arteriovenous malformations (AVM), a common cause of chronic GI bleeding, are notoriously difficult to find in the small bowel. They are flat and not visualized on small bowel X-rays. They can develop in the distal small bowel and thus not be reachable by scopes.

The primary indication for capsule endoscopy is evaluating obscure/occult GI bleeding. These patients have anemia, recurrent visible or occult GI bleeding and negative EGD and colonoscopy, implying a small bowel source. Within the small bowel, tumors, arteriovenous malformations (AVM), ulcers, inflammation (Crohn’s disease and others) can be visualized by capsule endoscopy.  

Current indications for use of capsule endoscopy include:

• Evaluate GI bleeding thought originating from a small bowel source.

• Evaluate abnormalities seen on small bowel X-rays or CT scans.

• Chronic diarrhea.

• Evaluate rarer genetic polyposis syndromes that may involve the small bowel.

• Evaluate for subtle inflammation (Crohn’s disease) not found on other types of examinations.

The time involved to complete an exam with capsule endoscopy is significant. The patient fasts beginning 10 p.m. the night before. The battery is activated simply by taking the capsule out of the package which removes it from a magnet, which kept the switch off. The capsule is ingested in the morning and clear liquids are allowed for the next 2 hours – solid food could cloud the lens and obstruct the view. The patient returns 7-8 hours later and the sensor array and belt are removed. The information is downloaded by the endoscopy nurse into a desktop or laptop computer. The images are viewed and a report is prepared, a process that takes 60-90 minutes. The “video” created by stringing photos together can be viewed from one frame at a time to 25 frames per second. It usually takes about 1 hour to transit thru stomach and 4-5 hours thru small bowel into the colon. The small bowel images are then viewed for abnormalities (bring popcorn for this 60-90 minute “movie”). There is some control over the speed of the ‘film.’ Individual photos of abnormalities are selected, book marked and annotated. These images can be included in a report or emailed. The entire file can be saved to a disc or transmitted electronically for viewing at a more convenient location, if desired.

What about the claims and hopes of the media and public?

No discomfort or complications?

For some, just swallowing this rather large pill may be briefly uncomfortable. There is no sensation associated with the capsule as it passes down the GI tract. The capsule could lodge itself at an area of narrowing producing a bowel obstruction, requiring surgery. Thus, a patient who is not a surgical candidate probably should not undergo capsule endoscopy. This complication has been reported only once (so far).

No prep?

True, there is no laxative needed since the colon is not being examined. The small bowel usually stays free of significant debris.

Noninvasive?

This technique is considered non-invasive and does not even require an I.V.

Improved accuracy?

In patients with occult GI bleeding who have had a negative workup capsule endoscopy has found abnormalities in the small bowel in 60%. Since we are now using the first generation of this device, as the technology improves, the accuracy will increase even further.

Replace colonoscopy?

Not now or in the near future. Capsule endoscopy currently does not visualize the colon. Future models might allow visualizations from both ends of the capsule, improving ability to peer behind folds etc. We look forward to potential future uses in the colon (and elsewhere). 

Belt with sensor array detectors

Inner workings of the capsule

Superficial blood vessel (angiodysplasia) as cause of anemia