The major problem being addressed is whether there is a link between cutaneous vasculature and skin diseases. So far, many research groups noticed that there are skin vasculature changes when there are skin diseases, but how to link the vasculature with diseases remain an open topic due to the lack of proper methods. This project aims to explore the use of optical coherence tomography angiography (OCTA) and photoacoustic tomography (PAT) to answer this question. Since OCTA can visualize the superficial plexus of human cutaneous vasculature and PAT can image the deep plexus of human cutaneous vasculature, combining OCTA and PAT should be able to give people a method to visualize in 3D the complete human cutaneous vasculature. When the whole vasculature is extracted from different patients, we can then analyze the vasculature in a quantitative manner so that a parametric approach can be taken to help accurate diagnosis of skin diseases directly using skin vasculature information.
In this action, a cohort of 66 human subjects were recruited and imaged using the OCTA machine developed within this project. These human subjects consisted of people suffering from various stages of chronic venous insufficiency (CVI). The wide span from healthy subjects to skin ulcer subjects generated a complete spectrum of the disease progression. OCTA imaging was applied in a painless and non-invasive manner. All the images were then quantitatively analyzed. It was noticed that, along with the progression of the disease, skin vasculature showed different patterns. The quantitative analysis done in a parametric way was then confirmed by clinicians. This is the first study when OCTA was used for this type of phlebological disease. The microvasculature resolved using OCTA gave the clinicians a new way to help triage and treat skin diseases. Because CVI is affecting a huge portion of the elderly population, whereas OCTA scan is completely painless and non-invasive, the work carried out in this action has the potential to provide a new tool in the phlebology diagnosis procedure.
On top of OCTA, a PAT system was also developed and applied in clinical imaging. It was proven that with the help of PAT, the image penetration depth can be significantly enhanced. The combination of OCTA-PAT can therefore be used in wider applications in dermatology in addition to phlebology.
