Is Autofluorescence Imaging Endoscopy Useful for Determining the Depth of Invasion in Gastric Cancer

Abstract

Background/Aims: Newly developed autofluorescence (AF) imaging (AFI) endoscopy can detect AF emitted by the gastrointestinal wall and may reliably detect tumors or inflammation that block AF. However, the efficacy of AFI endoscopy has not been evaluated for diagnosing the depth of tumor invasion in gastric cancer. Methods: AF endoscopic images were split into three bands (R, G and B) and expressed as grayscale values. AF indices, defined as the ratio of the G band image grayscale value to that of the R band, were calculated preoperatively. Correlations of AF indices with invasion depth and tumor thickness were assessed. AF indices were calculated preoperatively for 72 gastric cancer lesions without ulceration in 67 patients. The invasion grade of the lesions was classified histologically into 5 groups: M, SM, MP, SS and SE. Results: The mean tumor AF indices for each depth stage were 0.99, 0.77, 0.75, 0.74 and 0.61, respectively. A statistically significant difference was found between group M and the other groups. Conclusion: AFI endoscopy may reliably determine the depth of gastric cancer tumor invasion, although an expanded study comprised of larger numbers of subjects and different types of cancers may be required to clearly demonstrate its validity.

Research Progress of Autofluorescence Imaging Technology in the Diagnosis of Early Gastrointestinal Tumors

“…More than 50% of early gastric carcinoma showed well-defined pink lesions under AFI, while its surrounding mucosa showed a green background, which suggested that mucosa presented changes of atrophic gastritis. 26 Otani et al 27 used the principle of red-green hue contrast between lesions under AFI and its surrounding normal tissues, proposing the concept of “Green-Red ratio (G/R ratio).” And then their team performed AFI to detect 72 non-ulcerative gastric carcinoma lesions, finding that the average AF index of intramucosal carcinoma was 0.99, which was significantly different from that of submucosal carcinoma and invasive carcinoma, suggesting that AFI could be used to evaluate the depth of longitudinal invasion of gastric carcinoma. In the prospective cohort study of Tada et al 28 endoscopists from 2 groups, that is, the senior group and less clinical experience group (5 endoscopists in each group), evaluated 50 gastric lesions (20 early cancer lesions and 30 benign lesions) by using white-light endoscopy and AFI, respectively.…”

Advanced Imaging Technology Other than Narrow Band Imaging

“…2 , 3 ). Otani et al [ 15 ] reported that AFI endoscopy was also helpful for evaluating the depth of tumor invasion in gastric cancers without ulceration.…”

Normalized autofluorescence imaging diagnostics in upper GI tract: a new method to improve specificity in neoplasia detection

“…Such methods as Optical Coherence Tomography [15,16], Laser Scattering Spectroscopy [17], Raman Spectroscopy [18], Confocal Laser Endomicroscopy [19], Chromoendoscopy [20,21], Magnification Chromoendoscopy [22], Infrared Endoscopy [23] and Spectral Imaging, particularly Fluorescence Imaging including Autofluorescence Imaging (AFI) [24,25] and Narrow Band Imaging (NBI) [26] have been successfully applied in the GI tract including esophagus and stomach, for biopsy guidance and microsurgery navigation [27][28][29][30][31]. Recently, WLE, AFI and NBI have been incorporated into one system: endoscopic tri-modal imaging [32,33].…”