FICE -- A New Imaging Tool
Colonoscopy is considered the gold standard for finding and removing – and possibly preventing – colorectal cancer. It can detect up to 95% of colon cancers and can be used to remove precancerous polyps before they develop into cancer. Today researchers are working to make colonoscopy an even better screening tool. One new imaging system in development is the Fuji Intelligent Chromo Endoscopy (FICE).
As with narrow-band imaging, FICE also narrows the bandwidth of conventional white-light colonoscopy to improve visualization, but it creates this effect electronically. Using special software, FICE takes the image transmitted from the white-light colonoscope and creates a "virtual" image at predetermined wavelengths.
The virtual image shows minute details in the polyp and the colon lining that can't be seen using standard colonoscopy. As with narrow-band imaging, the doctor can, with the push of a button, alternate between the white-light-generated image and the virtual one.
FICE is beneficial in the same way as narrow-band imaging. Research shows that it likely doesn't improve polyp detection, compared with white-light colonoscopy, but it does help differentiate cancerous and precancerous polyps from benign polyps. What's more, it may do it even better than narrow-band imaging. In a 2009 study in Gastrointestinal Endoscopy, the overall accuracy of FICE in identifying cancerous and noncancerous polyps during colonoscopy was 98%.
While the FICE device is commercially available, it is a newer technology than narrow-band imaging and its benefits in accurately identifying benign versus cancerous polyps require confirmation in larger studies.
From John Hopkins University
Friday, January 28, 2011
Wednesday, January 5, 2011
Narrow Band Colonoscopy
Mixed Results on Narrow-Band Imaging
A standard colonoscope uses a regular white light to illuminate the colon. Narrow-band imaging uses an optical filter to produce blue light, which provides more contrast between the polyp and the colon lining. At the push of a button, a colonoscope with narrow-band imaging capabilities can switch between white light and blue light. Blue light has a narrower wavelength, which is why the device is called "narrow-band" imaging.
Researchers hypothesized that narrow-band imaging would improve a doctor's ability to find polyps. But clinical trials have shown mixed results, with one randomized study reporting improved polyp detection and three others showing it was no better than standard white-light colonoscopy. Based on these results, narrow-band imaging will likely not be used to improve detection of polyps.
Where narrow-band imaging appears most promising, however, is in differentiating benign polyps from those that are cancerous or precancerous. Today, the standard of practice is to remove all polyps and send them to the pathology lab for analysis. But about a third of these polyps end up being benign and thus were removed unnecessarily, putting the patient at risk -- albeit a small risk -- for bleeding complications.
Narrow-band imaging can visualize differences in surface and blood vessel patterns that can help determine whether or not a polyp is cancerous. So far, six well-designed studies have investigated whether narrow-band imaging can be used accurately to differentiate polyp types during colonoscopy. These studies found that using narrow-band imaging, doctors could accurately identify suspicious and benign polyps about 80 to 90% of the time.
Although a narrow-band imaging colonoscope called Exera is commercially available, more research and refinement of this technology are necessary to bring the accuracy rate closer to 100%. If this level of accuracy is reached, doctors could begin diagnosing polyps during colonoscopy, removing only those that are life-threatening and leaving benign ones in place.
A standard colonoscope uses a regular white light to illuminate the colon. Narrow-band imaging uses an optical filter to produce blue light, which provides more contrast between the polyp and the colon lining. At the push of a button, a colonoscope with narrow-band imaging capabilities can switch between white light and blue light. Blue light has a narrower wavelength, which is why the device is called "narrow-band" imaging.
Researchers hypothesized that narrow-band imaging would improve a doctor's ability to find polyps. But clinical trials have shown mixed results, with one randomized study reporting improved polyp detection and three others showing it was no better than standard white-light colonoscopy. Based on these results, narrow-band imaging will likely not be used to improve detection of polyps.
Where narrow-band imaging appears most promising, however, is in differentiating benign polyps from those that are cancerous or precancerous. Today, the standard of practice is to remove all polyps and send them to the pathology lab for analysis. But about a third of these polyps end up being benign and thus were removed unnecessarily, putting the patient at risk -- albeit a small risk -- for bleeding complications.
Narrow-band imaging can visualize differences in surface and blood vessel patterns that can help determine whether or not a polyp is cancerous. So far, six well-designed studies have investigated whether narrow-band imaging can be used accurately to differentiate polyp types during colonoscopy. These studies found that using narrow-band imaging, doctors could accurately identify suspicious and benign polyps about 80 to 90% of the time.
Although a narrow-band imaging colonoscope called Exera is commercially available, more research and refinement of this technology are necessary to bring the accuracy rate closer to 100%. If this level of accuracy is reached, doctors could begin diagnosing polyps during colonoscopy, removing only those that are life-threatening and leaving benign ones in place.
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