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Imaging
Tethered capsule en face optical coherence tomography for imaging Barrett’s oesophagus in unsedated patients
  1. Kaicheng Liang1,
  2. Osman O Ahsen1,
  3. Annalee Murphy2,
  4. Jason Zhang1,
  5. Tan H Nguyen1,
  6. Benjamin Potsaid1,
  7. Marisa Figueiredo2,
  8. Qin Huang2,3,
  9. Hiroshi Mashimo2,4,
  10. James G Fujimoto1
  1. 1Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
  2. 2Gastroenterology, VA Boston Healthcare System, Boston, Massachusetts, USA
  3. 3Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
  4. 4Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
  1. Correspondence to Professor James G Fujimoto; jgfuji{at}mit.edu

Abstract

Objective Barrett’s oesophagus (BE) screening outside the endoscopy suite can identify patients for surveillance and reduce mortality. Tethered capsule optical coherence tomography (OCT) can volumetrically image oesophageal mucosa in unsedated patients and detect features of BE. We investigated ultrahigh-speed tethered capsule swept-source OCT (SS-OCT), improved device design, developed procedural techniques and measured capsule contact, longitudinal pullback non-uniformity and patient toleration.

Design OCT was performed in 16 patients prior to endoscopic surveillance/treatment. Unsedated patients swallowed the capsule with sips of water and the tether was pulled back to image the oesophagus. SS-OCT at 1 000 000 A-scans/s enabled imaging 10 cm oesophageal lengths in 10 s with 30 µm transverse and 8 µm axial resolution. Capsule contact, longitudinal image coverage and patient toleration were assessed.

Results Nine patients had non-dysplastic BE, three had ablative treatment-naïve neoplasia and four had prior ablation for dysplasia. Dry swallows facilitated capsule transit through the lower oesophageal sphincter (LES), and waiting 10 s before pullback reduced swallow induced LES relaxation. Slow nasal inhalation facilitated capsule retrieval and minimised gag reflex. The procedure was well tolerated. Ultrahigh-speed SS-OCT generated cross-sectional and subsurface en face images showing BE features, while subsurface en face images were required to assess the gastro-oesophageal junction. Candidate features of dysplasia were also identified which could inform follow-up endoscopy/biopsy. BE features were seen in all patients with histologically confirmed BE. Mean capsule contact over BE was 75%±27% for all patients and better in short segment BE. Mean longitudinal image coverage over BE was 59%±34% and better for long segment BE.

Conclusions Ultrahigh-speed tethered capsule SS-OCT can image en face and cross-sectional mucosal features over wide areas. Device and procedure optimisation improved performance. BE features could be identified in all patients, but limited capsule contact and longitudinal coverage could cause sampling errors for focal pathologies.

  • Barrett's oesophagus
  • imaging
  • screening
  • surveillance
http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

https://doi.org/10.1136/bmjgast-2020-000444

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    Footnotes

    • Contributors KL, JGF and HM designed the study. KL, OOA and BP developed the OCT imaging technology. KL, OOA, AM, JZ, THN, MF and HM collected the data. KL, OOA, JGF and HM analysed the data. QH made the histological diagnoses. JGF and HM obtained funding for the study. KL, JGF and HM wrote the manuscript. All authors read and contributed to the manuscript. JGF and HM were principal investigators for this study.

    • Funding National Institutes of Health grants R01-CA075289-21 (JGF and HM) and R44CA235904- 02 (JGF), Veterans Administration Innovation Award (HM), graduate fellowship from Agency for Science, Technology and Research, Singapore (KL).

    • Competing interests None declared.

    • Patient consent for publication Not required.

    • Ethics approval The study was approved by IRBs at the Veterans Affairs Boston Healthcare System, Harvard Medical School and Massachusetts Institute of Technology.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data availability statement Data are available on reasonable request. Study data (OCT images, toleration scores) deidentified of patient information is available on reasonable request from the investigators and with approval from the Research Committees at the VA Boston Healthcare System, Harvard Medical School and MIT.