Feasibility of using optical coherence tomography to detect acute radiation-induced esophageal damage in small animal models

Abstract

"Feasibility of using optical coherence tomography to detect acute radiation-induced esophageal damage in small animal models," J. Biomed. Opt. 23(4), 046004 (2018), doi: 10.1117/1.JBO.23.4.046004. Abstract. Lung cancer survival is poor, and radiation therapy patients often suffer serious treatment side effects. The esophagus is particularly sensitive leading to acute radiation-induced esophageal damage (ARIED). We investigated the feasibility of optical coherence tomography (OCT) for minimally invasive imaging of the esophagus with high resolution (10 μm) to detect ARIED in mice. Thirty mice underwent cone-beam computed tomography imaging for initial setup assessment and dose planning followed by a single-dose delivery of 4.0, 10.0, 16.0, and 20.0 Gy on 5.0-mm spots, spaced 10.0 mm apart in the esophagus. They were repeatedly imaged using OCT up to three months postirradiation. We compared OCT findings with histopathology obtained three months postirradiation qualitatively and quantitatively using the contrast-to-background-noise ratio (CNR). Histopathology mostly showed inflammatory infiltration and edema at higher doses; OCT findings were in agreement with most of the histopathological reports. We were able to identify the ARIED on OCT as a change in tissue scattering and layer thickness. Our statistical analysis showed significant difference between the CNR values of healthy tissue, edema, and inflammatory infiltration. Overall, the average CNR for inflammatory infiltration and edema damages was 1.6-fold higher and 1.6-fold lower than for the healthy esophageal wall, respectively. Our results showed the potential role of OCT to detect and monitor the ARIED in mice, which may translate to humans. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Optical coherence tomography to detect acute esophageal radiation‐induced damage in mice: A validation study

“…While mice in the test group underwent irradiation and OCT imaging, radiation‐only and OCT‐only control groups received only irradiation or OCT imaging, respectively. Based on a previous study, where limited ARIED was detected, we chose a single‐fraction dose level of 40 Gy on two 10.0‐mm‐diameter spots spaced about 10.0 mm apart and irradiated with two orthogonal beams to the esophagi of mice in the test group. We performed OCT imaging at two, three, and seven days after irradiation for the test and OCT‐only groups.…”

“…The system uses commercially available C7 Dragonfly intravascular imaging probes (St. Jude Medical) designed for percutaneous coronary intervention. The OCT probe had an outer diameter of 0.9 mm with a rotating fiber and utilized a longitudinal pullback to obtain 3D imaging . The pullback length was about 6 cm and the axial and lateral resolutions were 15.0 and 30.0 μm, respectively .…”

“…The OCT probe had an outer diameter of 0.9 mm with a rotating fiber and utilized a longitudinal pullback to obtain 3D imaging . The pullback length was about 6 cm and the axial and lateral resolutions were 15.0 and 30.0 μm, respectively . All mice were anesthetized and received probe insertion with one hand while the animals were being held by the scruff of the neck with the other hand .…”

“…The pullback length was about 6 cm and the axial and lateral resolutions were 15.0 and 30.0 μm, respectively . All mice were anesthetized and received probe insertion with one hand while the animals were being held by the scruff of the neck with the other hand . During the probe insertion, it was advanced carefully while the tongue was visible to avoid damage .…”

“…All mice were anesthetized and received probe insertion with one hand while the animals were being held by the scruff of the neck with the other hand . During the probe insertion, it was advanced carefully while the tongue was visible to avoid damage . The probe was inserted until we felt resistance by the stomach valve.…”