Chromoendoscopy in magnetically guided capsule endoscopy

EXPERIMENTAL ASSESSMENT OF INTACT COLON DEFORMATION UNDER LOCAL FORCES APPLIED BY MAGNETIC CAPSULE ENDOSCOPES

Magnetically guided capsule endoscopy is a promising technology for clinical application. A platform that simulates the magnetic capsule endoscope system is built to study the deformation process of the colon when its lumen suffers local forces. Force-displacement curves of the porcine large intestine under various experiment conditions, including different loading positions (haustra or taeniae coli), loading directions, colon inner pressures and specimen lengths, were measured to analyze the mechanical behavior of the intact large intestine during interactions with magnetic capsule endoscopes. In the practical application of the magnetic capsule endoscope, these data are imperative to optimize the control scheme and reduce operation risks. Based on our experiments, the taeniae coli of the intact large intestine show higher linear stiffness than the haustra, and inflation reduces the linear stiffness of the colon. Magnetic capsule with small edge radii can more easily damage or even perforate the colon. Based on our test results, we suggest that the force applied to the colon should be limited to below 17[Formula: see text]N when the capsule is actuated forward along the colon and limited to below 10[Formula: see text]N when the capsule is vertical to the colon during lesion screening.

Microdissection of Human Esophagogastric Junction Wall with Phase-contrast X-ray CT Imaging

Phase-contrast x-ray imaging using an x-ray interferometer has great potential to reveal the structures inside soft tissues, because the sensitivity of this method to hydrogen, carbon, nitrogen, and oxygen is about 1000 times higher than that of the absorption-contrast x-ray method. In this study, we used phase-contrast X-ray CT to investigate human resected esophagogastric junction. This technology revealed the three-layer structure of the esophagogastric junction wall-mucous, submucosa and muscular layers. The mucous and muscular layers were clearly separated by a loose submucosa layer with a honeycomb appearance. The shape of the mucous and muscular layers was intact. The boundary between the mucous and submucosa layers was distinct, as was the border of the muscular and submucosa layers. The surface of the esophagogastric junction was displayed clearly through 3D reconstruction. The technology might be helpful in the diagnosis of esophagogastric junction lesion, especially for the early adenocarcinoma.

Investigation of gastric cancers in nude mice using X-ray in-line phase contrast imaging

Background

This paper is to report the new imaging of gastric cancers without the use of imaging agents. Both gastric normal regions and gastric cancer regions can be distinguished by using the principal component analysis (PCA) based on the gray level co-occurrence matrix (GLCM).

Methods

Human gastric cancer BGC823 cells were implanted into the stomachs of nude mice. Then, 3, 5, 7, 9 or 11 days after cancer cells implantation, the nude mice were sacrificed and their stomachs were removed. X-ray in-line phase contrast imaging (XILPCI), an X-ray phase contrast imaging method, has greater soft tissue contrast than traditional absorption radiography and generates higher-resolution images. The gastric specimens were imaged by an XILPCIs’ charge coupled device (CCD) of 9 μm image resolution. The PCA of the projective images’ region of interests (ROIs) based on GLCM were extracted to discriminate gastric normal regions and gastric cancer regions. Different stages of gastric cancers were classified by using support vector machines (SVMs).

Results

The X-ray in-line phase contrast images of nude mice gastric specimens clearly show the gastric architectures and the details of the early gastric cancers. The phase contrast computed tomography (CT) images of nude mice gastric cancer specimens are better than the traditional absorption CT images without the use of imaging agents. The results of the PCA of the texture parameters based on GLCM of normal regions is (F₁ + F₂) > 8.5, but those of cancer regions is (F₁ + F₂) < 8.5. The classification accuracy is 83.3% that classifying gastric specimens into different stages using SVMs.

Conclusions

This is a very preliminary feasibility study. With further researches, XILPCI could become a noninvasive method for future the early detection of gastric cancers or medical researches.