Infrared imaging to help monitor pulmonary fibrosis

Diagnosis of pulmonary fibrosis involves a comprehensive multidisciplinary discussion between a pulmonologist, radiologist and pathologist. The traditional pathological examination involves chemical staining and requires the subjective evaluation by a pathologist to determine the percentage and grade of fibrosis. Infrared imaging is a label-free technique, nondestructive approach that gives a biochemical fingerprint of the entire tissue which includes the measurement of key cellular and tissue biomarkers within tissues such as proteins, lipids, collagen cross linking and glycosylation.

Researchers at the University of Illinois Chicago used the bleomycin-included model of pulmonary fibrosis, wherein the IR spectra was acquired from the entire lung tissue sections. Spectral ratio analysis and multivariate analysis of the pre-processed IR spectra extracted from each pixel of the lung tissues revealed the changes in the biochemical fingerprint across different regions of the lung and at different stages of fibrosis. Principal component analysis and linear discriminant analysis could clearly distinguish different stages of the diseases, as studied using the bleomycin included model of pulmonary fibrosis.

This study was pursued in the laboratories of Michael Walsh and Viswanathan Natarajan at UIC and was published in July 2020 in the Journal of Biomedical Optics. Vidyani Suryadevara was the first author. The unique advantage of this technique is not only that the tissue could be reused for other purposes, but also that it is an automated way for histopathological examination.

This work is a collaboration between UIC, Rush University, Brookhaven National Laboratory and Medical University of South Carolina and is being further expanded to study human samples. Thus, IR imaging holds the potential to be a powerful adjunct to current histopathological techniques in finding better ways to understand, manage and develop novel therapeutics for fibrotic diseases.