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The View From Inside
For colonoscopy, good visualization is getting better.
Seth Gross
Publish Date: March 24, 2014   |  Tags:   Gastroenterology
endoscopic visualization WHAT'S AHEAD Innovations are significantly improving endoscopic visualization, says Seth A. Gross, MD, FACG, FASGE.

The latest advances in colonoscopy help physicians inspect the surface of the colon more effectively to identify and remove more polyps and adenomas. Scope manufacturers continue to push the innovation envelope, offering optical and mechanical advances to flexible endoscope designs that have drawn physicians' attention for their potential to improve patient care. Here's a look at a few buzz-worthy devices.

Expanded viewpoints
Traditional colonoscopy is based on a forward view, seeing only what's directly ahead as the scope is withdrawn. Two new endoscopes' optical enhancements are expanding this standard view, though, significantly improving visualization by shedding light on potentially challenging areas.

One of the scopes, the Fuse Full Spectrum Endoscopy colonoscope by EndoChoice, employs 3 CCD imaging chips and 7 LEDs (3 at the front and 2 on each side) to nearly double the field of view to 330 degrees. The panoramic video image it captures is displayed across 3 adjacent monitors, with 1 screen showing the straight-ahead view and the others, angled 45 degrees on the left and right sides, providing peripheral views, similar to the way a car's side-view mirrors would. The wider view enables a more thorough examination of the colon's lining.

In another scope, increased distal-end articulation offers an improvement on visualization. The narrower retroflex radius of the RetroView Video Colonoscope from Pentax allows 210 degrees of angulation. This maneuverability gives physicians easier access to the proximal side of folds and flexures in the colon lining, where polyps might be particularly challenging to spot.

Medivator's Endocuff Endoscopic Overtube SCOPE ASSISTANCE Medivator's Endocuff Endoscopic Overtube makes it easier for physicians to inspect both the front and the back sides of folds in the colon.

Additional assistance
Not every advance in colonoscopy visualization arrives through the camera lens. Some innovations lend an internal hand instead. A pair of mechanical innovations to the design of standard endoscopes can literally smooth the way to better screening colonoscopies.

During insertion, the flexible arms on Medivators' EndoCuff Endoscopic Overtube are folded down against the tip of the scope. As the scope is withdrawn, however, they umbrella out to flatten folds in the lining of the colon, making it easier for physicians to inspect both the front and the back sides of the folds. The single-use device also serves as a stabilizing handbrake, preventing the scope from slipping and keeping its view steady as instruments are inserted through the biopsy channel.

The G-Eye Endoscope from Israeli manufacturer Smart Medical Systems hasn't yet received the Food and Drug Administration's 510(k) approval for sale in the U.S. market, but it's already in use among European endoscopists. It's a standard scope with a reusable balloon built in at the distal end. At different levels of inflation, the balloon can straighten folds and open difficult-to-see sections of the colon for inspection, or stabilize and anchor the scope during therapeutic action.

CLINICAL RESULTS
The Effects of Enhanced Endoscopy

EndoChoice's Fuse supplements TRIPLE TRIAL EndoChoice's Fuse supplements the forward view with peripheral vision.

Clinical reviews of the effectiveness of Medivators' EndoCuff Endoscopic Overtube and the G-Eye Endoscope from Smart Medical Systems in improving colonoscopies are still underway. The earliest, manufacturer-funded studies of EndoChoice's Fuse Full Spectrum Endoscopy system, however, have been impressive.

According to a study published in the March issue of the journal Lancet Oncology (tinyurl.com/llq65ev), Fuse's full-spectrum endoscopy is superior to standard, forward-view colonoscopy in terms of adenoma miss rates. Researchers at surgical facilities in Israel, the U.S. and the Netherlands report that while forward-view missed 41% of adenomas (20 out of 49 in 15 patients), full-spectrum missed only 7% (5 out of 67 in 5 patients).

Since previous studies have marked forward-view's typical miss rate at 24% and 31%, this could prove a colossal improvement. "Full-spectrum endoscopy represents a technology advancement for colonoscopy and could improve the efficacy of colorectal cancer screening and surveillance," the researchers write

These preliminary results are promising. However, more time and research — including studies showing reproducible results — may be needed to change a majority of physicians' practice patterns.

What time will also tell — in the form of sustained, practical use — is whether these endoscopic innovations will revolutionize care. Consider, for instance, contrast enhancement mode (also known as narrow-band imaging), an endoscopic technology that emerged around the same time as high definition did. Positioned as a "virtual chromoendoscopy," it used specific wavelengths of light (instead of dye) in order to highlight details in the tissue that weren't otherwise visible.

Many observers anticipated that this feature would be in use during every colonoscopy. While it certainly plays a useful role in select cases, allowing physicians to see subtle changes in mucosal patterns at the press of a button, it isn't often used for the full scope withdrawal. Additionally, a Mayo Clinic study published in the American Journal of Gastroenterology 2 years ago argues that HD narrow-band imaging endoscopy doesn't significantly increase the detection of polyps, adenomas or flat adenomas, or reduce the miss rate of polyps or adenomas, in comparison with HD white-light endoscopy (tinyurl.com/pp5u6cl).

Scope manufacturer Olympus has added an optical magnification function and improved the image freezing function in its new 190 series colonoscopes. Researchers from Indiana University in Indianapolis compared the abilities of the 190 series scopes against the company's earlier line of 180 scopes. In their study, published in the March 2014 issue of the journal Endoscopy (tinyurl.com/oyqjlp8), the 190 series showed "less image blurring, improved subjective quality of stored images, and increased proportion of high confidence endoscopic estimates of polyp histology, but did not improve accuracy in estimating polyp histology."

— Seth A. Gross, MD, FACG, FASGE

Innovation's real payoff
There are many factors that drive the need to upgrade technology as it advances, with greater efficiency, less-invasive techniques, economic benefits and physician recruitment among them. Administrators often want to know how the purchase and implementation of new equipment will pay off.

The value of enhancements to endoscopic visualization is clearly in their promise to vastly improve patient care. The potential impact is significant. Seeing polyps that might once have been overlooked opens the door to more effective risk stratification and planning of surveillance intervals for patients, a prevention strategy that ultimately saves lives. We're eagerly awaiting more data on these innovations' benefits to patients.