Artifact-suppressed dual-modality OCT-fluorescence endoscopic imaging of colitis in murine models.

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder that requires objective and repeatable assessment of both tissue structure and disease activity for proper management of the disease. Multimodal endoscopy combining optical coherence tomography (OCT) and fluorescence imaging offers complementary structural and functional contrast for this purpose. However, conventional double-clad fiber catheters often suffer from multipath interference artifacts that degrade structural image fidelity. Here, we present a fully integrated dual-modality endoscopic system enabling artifact-suppressed OCT alongside high-sensitivity fluorescence imaging. We utilized this system to longitudinally monitor the progression of dextran sulfate sodium (DSS)-induced colitis in mice in vivo. The imaging results revealed distinct stage-specific biomarkers, where acute inflammation was characterized by profound vascular permeability, while the chronic phase was distinguished by persistent thickening of the muscularis layer. An exploratory random forest classifier trained on these extracted features achieved a diagnostic accuracy of 96.7% in distinguishing different colitis states, with feature importance analysis confirming the synergistic value of combining both the structural and fluorescence information. This work establishes a robust multimodal endoscopic platform for non-invasive, longitudinal quantification of inflammatory burden in preclinical models, with potential applications in diagnostic imaging and treatment monitoring of gastrointestinal diseases.