Differentiation of murine colon pathology by optical and mechanical contrast using optical coherence tomography and elastography

Abstract

Colon pathologies including colon cancer and ulcerative colitis afflict hundreds of thousands of people in the United States. Clinical detection of colon diseases is generally performed through colonoscopy. However, these methods usually lack the sensitivity or resolution to detect diseased tissue at early stages. Even high resolution optical techniques such as confocal microscopy and optical coherence tomography (OCT) rely on structural features to detect anomalies in tissue, which may not be sufficient for early disease detection. If changes in tissue biomechanical properties precede morphological changes in tissue physiology, then mechanical contrast would enable earlier detection of disease. In this work, we utilized optical coherence elastography (OCE) to assess the biomechanical properties of healthy, cancerous, and colitis tissue. Additionally, the optical properties of each sample were also assessed as a secondary feature to distinguish tissue types. The Young’s modulus, as measured by the propagation of an elastic wave, of the healthy, cancerous, and colitis tissue was 10.8 ± 1.0 kPa, 7.12 ± 1.0 kPa, and 5.1 ± 0.1 kPa, respectively. The variations in the OCT signal intensity over depth, as measured by the slope-removed standard deviation of each A-scan was 5.8 ±.0.3 dB, 5.1 ± 0.4 dB, and 5.5 ± 0.2 dB for healthy, cancerous, and colitis tissue, respectively. This work shows OCT structural imaging combined with OCE can detect minute changes in colon tissue optical scattering and elastic properties, which may be useful for detection various colon diseases, such as colitis and colon cancer.