3D Colonoscopy Facilitates Detection of Precancerous Lesions

A new three dimensional (3D) endoscopy technology could make it easier for doctors to detect precancerous lesions in the colon.

Developed by researchers at MIT (Cambridge, MA, USA) participating in the Madrid-MIT M+Vision Consortium (Spain), the new technique, known as photometric stereo endoscopy (PSE), can capture topographical images of the colon surface along with traditional two-dimensional (2D) images. Originally developed as a computer vision technique, PSE can reproduce the topography of a surface by measuring the distances between multiple light sources and the surface. Those distances are used to calculate the slope of the surface relative to the light source, generating a representation of any bumps or other features.


The researchers had to modify the original technology for endoscopy, since there was no way to know the precise distance between the tip of the endoscope and the surface of the colon. To eliminate inherent distortions, the researchers filtered out spatial information from the smoothest surfaces. The resulting technology, which requires at least three light sources, does not calculate the exact height or depth of surface features, but creates instead a visual representation that allows the colonoscopist to determine if there is a lesion or polyp, including flatter lesions that traditional endoscopy usually misses.

The researchers built two prototypes, one 35 millimeters in diameter (too large to use for colonoscopy), and one 14 millimeters in diameter, the size of a typical colonoscope. In tests with an artificial silicon colon, they found that both prototypes could create 3D representations of polyps and flatter lesions. According to the researchers, the technology could be incorporated into newer endoscopes, since from a hardware perspective these endoscopes already have multiple lights and just require a software update to process photometric data. The study describing the technology was published in the July 2013 issue of the Journal of Biomedical Optics.

“In conventional colonoscopy screening, you look for these characteristic large polyps that grow into the lumen of the colon, which are relatively easy to see,” said senior author Nicholas Durr, PhD, a research fellow in the Madrid-MIT M+Vision Consortium. “However, a lot of studies in the last few years have shown that more subtle, nonpolypoid lesions can also cause cancer.”

The Madrid-MIT M+Vision Consortium was launched by the Comunidad de Madrid and MIT to capitalize on significant public investments in medical and research technology and expertise, and to help establish Madrid as a global biomedical research center.

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