Multimodal tissue imaging: using coregistered optical tomography data to estimate tissue autofluorescence intensity change due to scattering and absorption by neoplastic epithelial cells

Abstract

Abstract. Autofluorescence (AF) imaging provides valuable information about the structural and chemical states of tissue that can be used for early cancer detection. Optical scattering and absorption of excitation and emission light by the epithelium can significantly affect observed tissue AF intensity. Determining the effect of epithelial attenuation on the AF intensity could lead to a more accurate interpretation of AF intensity. We propose to use optical coherence tomography coregistered with AF imaging to characterize the AF attenuation due to the epithelium. We present imaging results from three vital tissue models, each consisting of a three-dimensional tissue culture grown from one of three epithelial cell lines (HCT116, OVCAR8, and MCF7) and immobilized on a fluorescence substrate. The AF loss profiles in the tissue layer show two different regimes, each approximately linearly decreasing with thickness. For thin cell cultures (<300 μm), the AF signal changes as AFðtÞ∕AFð0Þ ¼ 1 − 1.3t (t is the thickness in millimeter). For thick cell cultures (>400 μm), the AF loss profiles have different intercepts but similar slopes. The data presented here can be used to estimate AF loss due to a change in the epithelial layer thickness and potentially to reduce AF bronchoscopy false positives due to inflammation and non-neoplastic epithelial thickening. © 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.

Coregistered autofluorescence-optical coherence tomography imaging of human lung sections

“…7 Therefore, the AF signal associated with different components cannot be accurately determined by measuring the AF intensity at the tissue surface alone as the AF intensity is altered by the scattering and absorption of intervening layers. The AF intensity from each component is a measure of fluorophore content in situ.…”

A high-efficiency fiber-based imaging system for co-registered autofluorescence and optical coherence tomography

“…Therefore, we expect that the regions with strong AF signal include cartilage and dense connective tissue. Strictly speaking, however, the scattering and absorption of superficial layers affect the AF signal measured at the luminal surface [10]. Therefore, more comprehensive studies are required to interpret AF images and to relate them to the fluorescing airway components in conjunction with the scattering and absorption effects of superficial layers.…”

“…When used in combination, AF/OCT imaging can provide biochemical information co-localized with structural information, potentially enabling increased diagnostic sensitivity and specificity. For example, a combined AF/OCT system could quantify the fraction of AF loss due to collagen remodeling in the stroma by removing the fraction of AF loss due to epithelial scattering and absorption (attenuation) from the measured AF signal [10]. Additionally, colocalized AF/OCT may be of particular importance in the lung where commercial endoscopes allow wide-field AF imaging in the central airways but cannot be extended to the peripheral airways due to size constraints.…”

Correction of motion artifacts in endoscopic optical coherence tomography and autofluorescence images based on azimuthal en face image registration

“…[1][2][3][4][5] Specifically in the lung, OCT can visualize distal airway tissue structures at high resolution and when combined with autofluorescence imaging (AFI), can probe specific molecular components of airway tissue such as collagen and elastin. 2,6,7 Therefore, combined OCT-AFI systems can produce complementary information that may enable increased detection and characterization of structural and functional features associated with different lung diseases. Our group has previously reported a combined endoscopic OCT-AFI instrument using a double-clad fiber (DCF) catheter that is capable of detecting pulmonary nodules and vascular networks.…”