FluxData FD-1665 system used in cancer detection study

FluxData’s FD-1665 used in Image Enhancement Of Surface Microstructure On Mucosa For Polarimetric Endoscopy study

 

Katsuhiro Kanamori from Device Research Laboratory Advanced Research Division, Panasonic Corporation in Japan recently concluded their research into endoscopic imaging of gastric mucosa for the purpose of detecting colon cancer. FluxData’s FD-1665 Polarimetric imaging system was used as part of the research.

Cancer affects the gastric areas surrounded by pits in the gastric mucosa. The cancer is detected via change in texture patterns. Traditionally, these changes in texture are very difficult to detect with standard white light endoscopes.

The alternative to white light endoscopy is an invasive process in which indigo carmine blue fluid is sprayed on the tissue, allowing the observer to see pooling in the surface microgrooves. This process can cause damage/bleeding to the mucosa and rapid colorization inhibits further observation.

The issues associated with the spray have prompted research into non-invasive digital image processing. This process makes use of a “pseudo-indigo carmine image” created by using color intensity images from a conventional endoscope and executes nonlinear edge detection looking for concave groove areas that should appear darker as a result of generation of shadows. This method is not yet as effective as traditional spraying. The author is studying the extraction surface geometric information of the mucosa using polarimetric imaging instead of conventional intensity imaging.

Method for experiment:

The author’s method is image enhancement of mucosal surface using de-polarization properties of the backscattered light in the surface groove regions and deeper layers of the mucosa. Two pairs of parallel and crossed nicols polarimetric images are captured under differently linear polarized illumination, taking into account illumination from a slanted angle. The pairs are then subtracted to enhance the contrast of the surface structure. Finally, the image is enhanced using a space frequency enhancement process which amplifies the mesh-like pattern seen in indigo carmine sprayed images

The research compared two imaging systems:

A manually rotated polarizer set up

 

Real time polarimetric endoscopy (rigid scope) using FluxData’s FD-1665

 

This version allows for two polarization full color images to be provided in real time and simultaneously.

 

Results of experiment: color intensity vs polarimetric

Fig. 6 (A/B) shows previous color intensity imaging technique compared to the polarimetric in Fig. 6 (C/D).

From their experiments, researchers were able to conclude that:

  1. The author was able to apply a well-established subtracted polarized technique to the images of the mucosa surfaces and showed that this technique is substantially more effective than conventional intensity imaging.

  2. The AVSPI technique outlined in the paper is capable of not only removing the difference in image quality that results from oblique lighting to the surface that is common in endoscopy, but can also enhance poor image quality of the subtracted image that is due to different optical paths or non-uniform lighting.

  3. The extinction ratio difference between the prototype endoscope (using FluxData’s camera) and the manually-rotated setup has little to no effect on the quality of the AVSPIs showing that polarimetric endoscopy is practical.

 

For a full copy of the research paper, please contact Pano Spiliotis info(at)fluxdata.com

All images courtesy of Device Research Laboratory Advanced Research Division, Panasonic Corporation