Optical coherence tomography imaging of collagenous tissue microstructure

The engineering of new biomaterials requires an in-depth understanding of the structure and function of the native tissues. Optical coherence tomography (OCT) is a non-destructive technique that allows the visualization of the microstructure of biological tissues. The aim of this study was to determine if OCT could be used to identify geometric properties of tendons such as crimp pattern. Freshly harvested tendon tissue was imaged with OCT during the application of incremental axial strain. Loads were simultaneously recorded during imaging. Results revealed that birefringent banding perpendicular to the collagen fiber axis could be visualized and measured. This crimp banding disappeared at a very low strain. Birefringent banding parallel to the collagen fiber axis was also seen and it was observed that the number of parallel bands increased as strain increased. Stress-strain data was calculated and found to lie within the expected range. These results indicate that OCT may prove to be a useful tool for the non-destructive analysis of tissue microstructure.