Measuring Barrett's Epithelial Thickness with Volumetric Laser Endomicroscopy as a Biomarker to Guide Treatment.
BACKGROUND
Radiofrequency ablation (RFA) treatment outcomes vary for unknown reasons. One hypothesis is that variations in Barrett's epithelial thickness (BET) are associated with reduced RFA efficacy for thicker BET and strictures for thinner BET. Volumetric laser endomicroscopy (VLE) is an imaging modality that acquires high-resolution, depth-resolved images of BE. However, the attenuation of light by tissue and the lack of layering in Barrett's tissue challenge BET measurements and the study of relationships between thickness and RFA outcomes. We aimed to quantify BET and compared the reliability of standard and contrast-enhanced VLE images.


METHODS
Baseline VLE scans from BE patients without prior ablative therapy and a Prague (M) length of > 1 cm were obtained from the US VLE Registry. An algorithm was applied to the VLE images to flatten the mucosal surface and enhance the contrast of different esophageal wall layers. Subsequently, BET was measured by two independent VLE readers using both contrast- and non-contrast-enhanced datasets. In order to validate these adjusted images, intra- and interobserver agreements were calculated.


RESULTS
VLE scans from fifty-seven patients were included in this study. BET was measured at eight equidistant locations on the selected cross-sectional images at 0.5 cm intervals from the GEJ to the proximal-most extent of BE. The intra-observer coefficients of the two readers for the contrast-enhanced images were 0.818 (95% CI 0.798-0.836) and 0.890 (95% CI 0.878-0.900). The interobserver agreement for the contrast-enhanced images (0.880; 95% CI 0.867-0.891) was significantly better than for the original images (0.778; 95% CI 0.754-0.799).


CONCLUSION
We developed an algorithm that improves VLE visualization of the mucosal layers of the esophageal wall and enables rapid and reliable measurement of BET. Interobserver variability measurements were significantly reduced when using contrast enhancement. Studies are underway to correlate BET with treatment response.
['Levink|I J M|IJM|http://orcid.org/0000-0001-9825-8728', 'Wolfsen|H C|HC|', 'Siersema|P D|PD|', 'Wallace|M B|MB|', 'Tearney|G J|GJ|']
D000368:Aged D000465:Algorithms D001471:Barrett Esophagus D000066491:Clinical Decision-Making D004867:Equipment Design D000071041:Esophageal Mucosa D020701:Esophagoscopes D004945:Esophagoscopy D005260:Female D006801:Humans D007090:Image Interpretation, Computer-Assisted D007834:Lasers D008297:Male D008853:Microscopy D008875:Middle Aged D015588:Observer Variation D018579:Patient Selection D011237:Predictive Value of Tests D000078703:Radiofrequency Ablation D012042:Registries D015203:Reproducibility of Results
Radiofrequency ablation (RFA) Volumetric laser endomicroscopy (VLE) Barrett’s esophageal thickness (BET) Barrett’s esophagus (BE)