Diagnosis of Neoplasia in Barrett’s Esophagus using Vital-dye Enhanced Fluorescence Imaging

Summary

Vital-dye enhanced fluorescence imaging (VFI) is a novel in vivo technique that combines high-resolution epithelial imaging with exogenous topical fluorescent contrast to highlight glandular morphology and delineate neoplasia (high grade dysplasia and cancer) in the distal esophagus.

Abstract

The ability to differentiate benign metaplasia in Barrett’s Esophagus (BE) from neoplasia in vivo remains difficult as both tissue types can be flat and indistinguishable with white light imaging alone. As a result, a modality that highlights glandular architecture would be useful to discriminate neoplasia from benign epithelium in the distal esophagus. VFI is a novel technique that uses an exogenous topical fluorescent contrast agent to delineate high grade dysplasia and cancer from benign epithelium. Specifically, the fluorescent images provide spatial resolution of 50 to 100 μm and a field of view up to 2.5 cm, allowing endoscopists to visualize glandular morphology. Upon excitation, classic Barrett’s metaplasia appears as continuous, evenly-spaced glands and an overall homogenous morphology; in contrast, neoplastic tissue appears crowded with complete obliteration of the glandular framework. Here we provide an overview of the instrumentation and enumerate the protocol of this new technique. While VFI affords a gastroenterologist with the glandular architecture of suspicious tissue, cellular dysplasia cannot be resolved with this modality. As such, one cannot morphologically distinguish Barrett’s metaplasia from BE with Low-Grade Dysplasia via this imaging modality. By trading off a decrease in resolution with a greater field of view, this imaging system can be used at the very least as a red-flag imaging device to target and biopsy suspicious lesions; yet, if the accuracy measures are promising, VFI may become the standard imaging technique for the diagnosis of neoplasia (defined as either high grade dysplasia or cancer) in the distal esophagus.

Introduction

Over the last forty years, the incidence of esophageal adenocarcinoma (EAC) has increased significantly^1,2; yet due to late diagnosis, the five-year survival rate is less than 20%³. The current standard of endoscopic surveillance in BE, the precursor to EAC, is white light endoscopy with random four-quandrant forceps’ biopsies of the segment. Unfortunately, this technique often misses neoplasia, which can be flat, subtle and difficult to differentiate on standard white light imaging⁴. While there has been success in using confocal laser microscopy to highlight cellular features in vivo, lesions can still be missed d....

Protocol

NOTE: Informed consent was obtained from the patients. Also, this research has been performed in compliance with all institutional, national, and international guidelines for human welfare.

1. Prepare Computer

1. Turn laptop on and connect USB from the DVI2USB Capture Card.

2. Prepare Monitor

1. Connect DVI cable to monitor and PinP to allow the endoscopist to view videos from these screens rather than the computer.
2. Make sure the standing monitor is on and is set to DVI.
3. Connect PinP to the back of the Olympus system then press the input button on the ....

Results

Figure 1B depicts classic Barrett's Esophagus with no dysplasia surrounded on the borders by normal squamous epithelium. Beginning with the flatter squamous tissue, which is peripherally located and indicated by the blue arrows, a homogenous area of dull fluorescence is present with no glandular architecture. The green arrows indicate a circular green line surrounding the squamous tissue. This outline is artifact resulting from the cap of the endoscope. Moving to the centrally located Barrett's tissue, g.......

Discussion

With standard endoscopic surveillance, neoplasia in BE is often missed⁸ because benign metaplasia can be indistinguishable from high-grade dysplasia and adenocarcinoma. As a tool that would better enable gastroenterologists to remedy this currently unavoidable error, vital-dye enhanced fluorescence imaging highlights a tissue’s glandular morphology thereby providing a distinct feature to differentiate the tissue types. Moreover, by providing a field of view up to 2.5 cm, VFI enables endoscopists to pan o.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Filter*	Schott North America, Inc., Duryea, Pennsylvania	Not Applicable	495-nm long-pass filter
Halo Cap – Medium*	Barrx Medical	CP-002A
Processor*	Pentax	EPK-i
Multispectral Digital Microscope**	Not Applicable	Not Applicable
Kimwipes	Kimberly-Clark	KimTech Science	S-8115
Cidex	Advanced Sterilization Products	CIDEX OPA Solution
Proflavine hemisulfate (0.01% w/v)			FDA (IND 102,217)
Laser Diode*	Nichia Corporation	Not Applicable	455-nm
Image Capture*	Labview	Not Applicable
Spray Catheter	Olympus	Not Applicable
*Equipment specifics within Reference 6. **Equipment specifics within Reference 7