OCTA angiograms typically comprise en face maximum intensity projection (MIP) images, where MIPs have been shown to be superior to other projections. By using differences between sequential OCT images (usually cross-sectional B-scans) at the same location, caused by motion in the sample, OCT volumetric images can be processed to generate volumetric or two-dimensional representations of blood flow, angiograms, which distinguish structures containing flowing blood from the surrounding static tissue. Standard “structural” OCT uses interference to measure the echo arrival time and intensity of backscattered light to generate cross-sectional and volumetric images of optical scattering in tissue. With the introduction of optical coherence tomography angiography (OCTA), the study and visualization of the microvasculature is well underway in the human retina and, to a lesser extent, in human skin and animal models of human disease. However, due to the lack of accessible/available diagnostic modalities tailored to the microvasculature, knowledge of its precise role in disease pathogenesis and progression is lacking and no specifically microvascular therapies are currently available. Many studies have suggested that dysfunction in the microcirculation may be as important as dysfunction in larger blood vessels in the context of cardiovascular pathophysiology. These small vessels, the microvasculature, account for about 99% of blood vessels in adults and play a key role in oxygen transport and nutrient delivery to the tissue, as well as in waste and carbon dioxide removal. The microcirculation comprises the smallest elements of the circulatory system, a dense network of arterioles, capillaries, venules, and lymphatic vessels with a diameter of less than 150 μm. Wide adoption could enable studies and aggregation of data on a scale sufficient to develop reliable microvascular biomarkers for early detection, and to guide treatment, of microvascular disease. We perform quantitative analysis of OCTA images from different commercial and non-commercial instruments and samples and show OCTAVA can accurately and reproducibly determine metrics for characterization of microvasculature. We present each analysis step, including optimization of filtering and choice of segmentation algorithm, and definition of metrics. With the goal of contributing to standardization of OCTA data analysis, we report a user-friendly, open-source toolbox, OCTAVA (OCTA Vascular Analyzer), to automate the pre-processing, segmentation, and quantitative analysis of en face OCTA maximum intensity projection images in a standardized workflow. A wide variety of instruments, imaging protocols, processing methods and metrics have been used to describe the microvasculature, such that comparing different study outcomes is currently not feasible. Optical coherence tomography angiography (OCTA) performs non-invasive visualization and characterization of microvasculature in research and clinical applications mainly in ophthalmology and dermatology.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |