Tethered confocal endomicroscopy capsule for diagnosis and monitoring of eosinophilic esophagitis

Nima Tabatabaei,Qian Yuan,Dongkyun Kang,Wayne Shreffler,Robert W Carruth,Tao Wu,Minkyu Kim,Guillermo J Tearney,Jenny S Sauk,Norman S Nishioka,John Leung,Aubrey Katz

doi:10.1364/boe.5.000197

Abstract

Eosinophilic esophagitis (EoE) is an allergic condition that is characterized by eosinophils infiltrating the esophageal wall. The treatment of the disease may require multiple follow up sedated endoscopies and biopsies to confirm elimination of eosinophils. These procedures are expensive, time consuming, and may be difficult for patients to tolerate. Here we report on the development of a confocal microscopy capsule for diagnosis and monitoring of EoE. The swallowable capsule implements a high-speed fiber-based reflectance confocal microscopy technique termed Spectrally Encoded Confocal Microscopy (SECM). SECM scans the sample in one dimension without moving parts by using wavelength swept source illumination and a diffraction grating at the back plane of the objective lens. As the wavelength of the source is tuned, the SECM optics within the 7 x 30 mm capsule are rotated using a driveshaft enclosed in a 0.8 mm flexible tether. A single rotation of the optics covered a field of view of 22 mm x 223 µm. The lateral and axial resolutions of the device were measured to be 2.1 and 14 µm, respectively. Images of Acetic Acid stained swine esophagus obtained with the capsule ex vivo and in vivo clearly showed squamous epithelial nuclei, which are smaller and less reflective than eosinophils. Imaging of esophageal biopsies from EoE patients ex vivo demonstrated the capability of this technology to visualize individual eosinophils. Based on the results of this study, we believe that this capsule will be a simpler and more effective device for diagnosing EoE and monitoring the therapeutic response of this disease.

Highlights

Eosinophilic esophagitis (EoE) is a prevalent food allergy disorder that manifests by eosinophilic infiltration within the esophageal wall
The capsule is designed to perform near infrared reflectance confocal microscopy of luminal organs, especially for the diagnosis and monitoring eosinophilic esophagitis disease in unsedated patients
Optical performance tests demonstrate that this capsule has lateral and axial resolutions of 2.1 and 14 μm, which is sufficient for identifying individual eosinophils [12]

Summary

Introduction

Eosinophilic esophagitis (EoE) is a prevalent food allergy disorder that manifests by eosinophilic infiltration within the esophageal wall. The keys to treating of the disease are identification of the triggering food allergen and attenuation of local inflammation. The treatments include an iterative process of eliminating potential allergenic foods from a person’s diet and/or corticosteroids. Both treatment methods require that patients be followed up by sedated endoscopies with biopsy to confirm that the eosinophils have been eliminated. These endoscopic procedures are expensive, time consuming, and frequently difficult for patients, many of whom are children, to tolerate. By providing a less invasive and potentially less expensive method for evaluating the esophagus on the microscopic level, swallowable capsule endomicroscopy devices capable of resolving eosinophils have the potential to improve the standard of care in EoE

Methods

Results

Conclusion