To noninvasively distinguish between perfused and occluded vessels from OCT scans of the human retina.Methods
Two specific signatures of the vascular tree of the human retina do exist, the hyper-reflectivity from the top of the vessel, and the shadow due to light absorption by haemoglobin. This shadow effect is notorious on the retinal pigment epithelium (RPE) being responsible for the dark appearance of the perfused vascular network on OCT fundus images. While the hyper-reflectivity (due to the vessel) is always present, the shadow effect on the RPE only exists for perfused vessels. Thus, this method allows the discrimination between perfused and occluded vessels by a non-invasive OCT scan of the human retina.Results
The haemoglobin on perfused vessels act as a natural dye on optical coherence tomography data. By computing the integral of OCT A-scan values over specific layers, it was demonstrated the possibility to discriminate between perfused and occluded vessels of the human retina noninvasively. In addition, the extent of the perfused vascular network possible to identify on OCT fundus reference is similar to that of colour fundus photography, and notably allows the identification of the non-perfused vascular network which colour fundus photography do not.Conclusion
The presented method compares favourably to colour fundus photography in discriminating between normal and occluded vascular tree, within the same scan, and provides functional information noninvasively.