Clinical Applications of Angiographic Optical Coherence Tomography

Angiographic optical coherence tomography (OCTA) has rapidly found utility within many facets of medical research. Here OCTA algorithms are enabled on a commercial OCT system and verified through correlation with intra-vital light microscopy (IVM). While the vast majority of vessels were accurately measured, smaller vessels (<30µm) have a tendency to appear dilated in comparison to IVM. The technique was also expanded upon to facilitate the imaging of subcutaneous murine fibrosarcoma tumours, negating the requirement for an intra-vital window. It was found that vessel measurement sensitivity was sufficiently high such that the morphologies of vessels within tumours expressing unique vascular endothelial growth factor (VEGF) isoforms could be differentiated, potentially providing a new angle of approach in the study of anti-angiogenic treatments. OCTA was then applied to human studies of atopic dermatitis, where it was found that metrics corresponding to vessel depth and morphology could be correlated with the sub-clinical severity of the condition. Knowledge of this could be utilised to observe the therapeutic response to treatment, past the point of clinical remission. A range of image-processing techniques were also developed, including automatic segmentation of the epidermal layer within skin being utilised to quantify the degree of epidermal thinning in response to applied skin strain, calculation of the skin capillary loop density and the response of skin vessels to temperature and pressure.