| Optical Coherence Tomography (OCT) is an emerging optical imaging modality that is capable of imaging biological tissues with micron resolution and millimeter penetration depth. In clinical diagnostic imaging and pathology, OCT has helped fill a gap in terms of both resolution and imaging depth, in between traditional fluoroescence based microscopes and non-invasive organ level imaging. In this domain, OCT can be used both as an ex vivo pathological examination tool or in vivo imaging modality. OCT has been successful in ophthalmology owing to its excellent in vivo optical sectioning ability and penetration depth. Over the years, OCT has seen substantial progress in terms of application diversification and functionalities. In addition to being able to image more organs and tissues, OCT has been configured to be incorporated inside catheters, enabling wall structure imaging in luminal settings, for example, major blood vessels or the digestive tract. And other than anatomical structures, OCT has also been able to specifically map out flow or elasticity.;As OCT becomes more diversified, data obtained also become more diversified in terms of information but more complicated. For instance, in endovascular OCT (EV-OCT), data were acquired radially instead of the traditional raster scanning. Moreover, during the pullback scanning in EV-OCT, motion artefacts are severe and this restricts the amount of functional information to be obtained. Furthermore, as OCT imaging speed becomes faster, reaching as high as 3.2 MHz axial scan rate, flow imaging is obliged to undergo paradigm shift, particularly from conventional ultrasound practices.;The main goal of this thesis was to address the development and validation of a set of algorithms that tackle these problems we now face in modern OCT systems and increase the utility of information obtained. In this thesis, an experimental protocol was first developed for proper porcine carotid arterial EV-OCT imaging. The data obtained were then utilized for the first time to dynamically detect microvessels (vasa vasorum) in major arterial wall. Meanwhile optimized digital speckle noise removal was performed for the first time on Fourier domain EV-OCT system data to further facilitate vessel wall evaluation and microvessel detection. Lastly, a novel depth enhanced OCT microangiography algorithm was devised for in vivo microvascular imaging of malformed vascular networks of human skin with genetic origins for the first time. The significance of this thesis lies in the potential of helping better understand the mechanism, progression and the effect of therapeutic intervention on various vascular diseases such as atherosclerosis and hereditary hemorrhagic telangiectasia. Better preventive measures and treatment options can ultimately be devised with advanced understanding of vascular diseases formation. |
