Imaging of Aortic Valve Collagen Structure and Internal Deformations Using a Novel Digital Image Correlation Technique

Advancements in optics and digital imaging tools have often led to new insights into tissue structure. Newly available computer controlled lcd polarizing filters have provided unprecedented control over light waveforms and structure. Inexpensive digital cameras have many times greater color sensitivity. Our goal is to apply these new technologies to quantitative imaging of aortic valve structures in-situ. We have developed a new elliptically polarized light imaging system (EPLIS) and technique for imaging aortic valve tissues. This new technique reveals takes advantage of the birefringent property of collagen to reveal multi-layered collagen fiber and membrane valve structures that were previously unknown. Using digital imaging correlation (DIC) image analysis software (developed in-house), the new imaging technique allows direct measurement of the internal deformations of aortic valve specimens during controlled loading. We present our imaging and analysis techniques, along with time-lapse images showing the complex structure of the aortic valve and direct measurements of deformations under controlled loads.