Diagnostic Accuracy of
EB-OCT for the Microscopic Diagnosis of ILD
Early, accurate diagnosis of interstitial lung disease (ILD) informs prognosis and therapy, especially in idiopathic pulmonary fibrosis (IPF). Current diagnostic methods are imperfect. High-resolution computed tomography has limited resolution, and surgical lung biopsy (SLB) carries risks of morbidity and mortality. We performed a prospective diagnostic accuracy study of EB-OCT in patients with ILD with a low-confidence diagnosis undergoing SLB. Sensitivity and specificity of EB-OCT was 100% (95% CI: 75.8-100.0%) and 100% (79.6-100%), respectively, for both histopathologic Usual Interstitial Pneumonia (UIP) and clinical diagnosis of IPF. There was high agreement between EB-OCT and histopathology for diagnosis of ILD fibrosis pattern (weighted κ: 0.87, (0.72-1.0)).
Idiopathic pulmonary fibrosis (IPF) affects the subpleural lung but is considered to spare small airways. However, recent micro–computed tomography (micro-CT) studies demonstrated small airway reduction in end-stage IPF explanted lungs, raising questions about small airway involvement in early-stage disease. We used EB-OCT to evaluate small airways in early IPF and control subjects in vivo. EB-OCT demonstrated marked bronchiolar loss in early IPF (between 30% and 50%), even in areas minimally affected by disease, compared with matched control subjects. Stereology metrics showed that IPF-affected small airways were significantly larger, more distorted, and more irregular than in IPF-less affected sites and control subjects. These findings support small airway disease as a feature of early IPF, providing novel insight into pathogenesis and potential therapeutic targets.
Polarization-Sensitive Endobronchial Optical Coherence Tomography
(PS-EB-OCT) for Microscopic Imaging of Fibrosis in ILD
Polarization sensitive EB-OCT (PS-EB-OCT) is a functional extension of conventional EB-OCT with the added ability to simultaneously detect endogenous birefringence from organized tissues, such as collagen in fibrosis. We demonstrated the feasibility of PS-EB-OCT as a novel, minimally invasive imaging method for in vivo microscopic visualization and quantitative assessment of fibrosis in ILD. PS-EB-OCT accurately classified microscopic fibrosis pattern in UIP and non-UIP fILDs.
Vaping and Small Airway Fibrosis
Vaping, including the use of electronic cigarettes (e-cigarettes), has become increasingly prevalent, yet the associated long-term health risks are largely unknown. EB-OCT imaging performed in two patients showed small airway–centered fibrosis with bronchiolar narrowing and lumen irregularities. On biopsy, these patients had small airway-centered fibrosis, including constrictive bronchiolitis, with MUC5AC overexpression.
Distinguishing tumor from fibrosis in lung biopsies using PS-OCT
Currently, there is no method for rapid, non-destructive intraprocedural assessment of core-needle biopsy (CNB) specimens, which is essential in lung cancer for accurate histological diagnosis, molecular testing for therapeutic decision-making, and tumor biobanking for research. We demonstrate the feasibility of PS-OCT measurements to distinguish and quantify tumor, fibrosis, and normal parenchyma in fresh, intact lung CNB specimens. PS-OCT was able to classify CNB specimens with low tumor content (≤ 25%) from high-tumor content (> 25%) with high sensitivity and specificity, as compared to histology.
Other ongoing projects
EB-OCT for microscopic assessment of interstitial lung abnormalities (ILA).
Repeat EB-OCT for assessment of microscopic changes in pulmonary fibrosis over time.
Polarization-sensitive EB-OCT for quantitative imaging and monitoring of pulmonary fibrosis.
EB-OCT for assessment of post-acute sequelae of SARS-CoV-2 (PASC).