Multispectral imaging detects gastritis consistently in mouse model and in humans

Abstract

Gastritis constitutes the initial step of the gastric carcinogenesis process. Gastritis diagnosis is based on histological examination of biopsies. Non-invasive real-time methods to detect mucosal inflammation are needed. Tissue optical properties modify reemitted light, i.e. the proportion of light that is emitted by a tissue after stimulation by a light flux. Analysis of light reemitted by gastric tissue could predict the inflammatory state. The aim of our study was to investigate a potential association between reemitted light and gastric tissue inflammation. We used two models and three multispectral analysis methods available on the marketplace. We used a mouse model of Helicobacter pylori infection and included patients undergoing gastric endoscopy. In mice, the reemitted light was measured using a spectrometer and a multispectral camera. We also exposed patient's gastric mucosa to specific wavelengths and analyzed reemitted light. In both mouse model and humans, modifications of reemitted light were observed around 560 nm, 600 nm and 640 nm, associated with the presence of gastritis lesions. These results pave the way for the development of improved endoscopes in order to detect real-time gastritis without the need of biopsies. This would allow a better prevention of gastric cancer alongside with cost efficient endoscopies.

Figure 1

Gastric histology at 12 months in non-infected control (n = 12, a) and H. pylori infected mice (n = 12, b). Mononuclear cell infiltration and aggregates (arrow) are easily visible in the infected mucosa (scale bar 100 µm) (Photo L. Fiette, Institut Pasteur).

Figure 2

Evolution of mouse gastric mucosa inflammation after H. pylori infection. Values are means of histological score ± SD.

Figure 3

(A) Spectrometer setup and principle. The light reflected from the tissue is decomposed and measured all along the visual light spectrum. (B) Reflectance variations, normalized by the control group, measured using the spectrometer, at each time point (10 nm increment).

Figure 4

Reflectance variations obtained using the multispectral camera and normalized on the non-infected control group, for each monoband image and at each time-point of H. pylori infection.

Figure 5

Ratio of variation in the spectrum from patients with active inflammation compared with the reference spectrum from the control group. P values were obtained using Wilcoxon–Mann–Whitney test.

Figure 6

Images under white light from the control group (a) and gastritis patients (b). In the band at 560 nm, we observed that the tissue from the control group (c) was smooth, compared to the gastritis tissue (d) which presented black spots (arrow) and a non-uniform surface. The band at 560 nm highlighted areas with a wavy appearance (black circle) in the patients with inflammation (d).