The new kid on the block for advanced imaging in Barrett's esophagus: a review of volumetric laser endomicroscopy

Abstract

Advanced imaging techniques used in the management of Barrett's esophagus include electronic imaging enhancement (e.g. narrow band imaging, flexible spectral imaging color enhancement, and i-Scan), chromoendoscopy, and confocal laser endomicroscopy. Electronic imaging enhancement is used frequently in daily practice, but use of the other advanced technologies is not routine. High-definition white light endoscopy and random four quadrant biopsy remain the standard of care for evaluation of Barrett's esophagus; this is largely due to the value of advanced imaging technologies not having been validated in large studies or in everyday practice. A new advanced imaging technology called volumetric laser endomicroscopy is commercially available in the United States. Its ease of use and rapid acquisition of high-resolution images make this technology very promising for widespread application. In this article we review the technology and its potential for advanced imaging in Barrett's esophagus.

Keywords: advanced imaging; cancer; dysplasia; esophagus.

Conflict of interest statement

Conflict of interest statement: The authors declare no conflicts of interest in preparing this article.

Figures

Figure 1.

Schematic depicting how VLE functions to obtain a high-resolution image of the esophagus. VLE, volumetric laser endomicroscopy.

Figure 2.

(a) Nvision volumetric laser endomicroscopy console. (b) Nvision VLE optical probe with the centering balloon. (c) schematic of the balloon inflated in the esophagus with the probe imaging. VLE, volumetric laser endomicroscopy.

Figure 3.

VLE image of the gastric cardia showing vertical pit and crypt architecture, high surface reflectivity, poor image penetration, and presence of rugal folds. Scale bar is 1 mm. Reprinted from Wolfsen and colleagues [Wolfsen et al. 2015] with permission from Elsevier. VLE, volumetric laser endomicroscopy.

Figure 4.

(a) VLE image of normal squamous mucosa with the layered architecture without glands. Scale bar is 1 mm vertical and horizontal. (b) Corresponding normal histology (not from the same patient). VLE, volumetric laser endomicroscopy.

Figure 5.

(a) VLE image showing loss of layered architecture in the setting of no surface pits and crypts. The red arrow points to complete effacement. The green arrow points to partial effacement. (b) Atypical glands (yellow arrows) with loss of layered architecture. Scale bar is 1 mm vertical and horizontal. VLE, volumetric laser endomicroscopy.

Figure 6.

OCT scoring index (OCT-SI). A score greater than or equal to 2 is associated with a sensitivity of 83% and a specificity of 75% for dysplasia. The surface intensity is designated by a + and the subsurface intensity by ++. Reprinted from Leggett and colleagues [Leggett et al. 2015] with permission from Elsevier. *Glandular atypia is defined by the presence of irregular and/or dilated glands. OCT, optical coherence tomography; OCT-SI, optical coherence tomography scoring index.

Figure 7.

VLE diagnostic algorithm (VLE-DA) index. This VLE-DA had a sensitivity of 86% (95% CI 69–96) and a specificity of 88%. (95% CI, 60–99). Reprinted from Leggett and colleagues [Leggett et al. 2015] with permission from Elsevier. CI, confidence interval; VLE, volumetric laser endomicroscopy; VLE-DA, volumetric laser endomicroscopy diagnostic algorithm.

Figure 8.

Case showing a long segment of Barrett’s esophagus (a) that was previously biopsied twice and showed indefinite for dysplasia. VLE was performed that showed the focal abnormality (b) that allowed a targeted biopsy. The yellow arrows correspond to the area on endoscopy (a) and atypical glands on VLE (b). Scale bar is 1 mm vertical and horizontal in panel b. Reprinted from Trindade and colleagues [Trindade et al. 2015] with permission from Elsevier. VLE, volumetric laser endomicroscopy.