Simulating vascular leakage on optical coherence tomography angiography using an overlay technique with corresponding thickness maps.Br J Ophthalmol 2019BJ
To demonstrate a technique for using optical coherence tomography angiography (OCTA) to simulate leakage in eyes with diabetic macular oedema and determine the sensitivity and positive predictive value of detecting leaking microvasculature on OCTA using fluorescein angiography (FA) as the comparative norm.
6×6 mm OCT angiograms were overlaid with the corresponding OCT thickness maps. Microvascular abnormalities on the OCT angiogram underlying areas of thickening on the OCT thickness map were assumed to be leaking. Two independent readers blindly read the OCTA overlay images then the FA images cropped to the same approximate region to delineate areas of leaking microvasculature. The results were compared to determine the sensitivity and positive predictive value of OCTA for detection of leaking vessels.
28 eyes of 19 diabetic patients were included. Each eye demonstrated an average of seven leaking microvascular abnormalities on the OCTA images and 22 leaking abnormalities on the FA images. Sensitivity of leaking microvasculature detection by OCTA was 26.1% and positive predictive value was 68.4%. The correlation coefficient of the two readers' detection of leaking microvasculature was 0.605 for OCTA reads compared with 0.916 for FA.
OCTA as a whole can be used to simulate leakage, but currently, sensitivity of the technique is low. Further understanding of the OCTA technology may yield novel means of detecting retinal pathology.