Abstract
Purpose :
Optical coherence tomography angiography (OCTA), in which the movement of blood cells is accentuated, can visualize retinal vessels accompanied with blood flow, whereas the vascular imaging on optical coherence tomography (OCT) images is based on the reflectance intensity of vascular walls. We compared retinal vessels on fluorescein angiography (FA), OCTA, and en-face OCT images, representing plasma, blood cells, and vascular walls, in diabetic retinopathy (DR).
Methods :
Consecutive 33 eyes of 17 DR patients were retrospectively reviewed. FA images were obtained using HRA2 (Heidelberg Engineering), and OCTA and OCT images (3x3mm centered on the fovea) were simultaneously acquired using Optovue RTVue XR Avanti (Optovue, Inc.). We qualitatively evaluated the OCTA and en face OCT findings corresponding to the microaneurysms on FA images, and quantified the areas of the foveal avascular zone (FAZ) on three imaging systems using ImageJ (NIH), followed by the comparison between them.
Results :
Microaneurysms on FA images corresponded to saccular, fusiform, coiled, or curved capillaries on OCTA images and round, oval, or ringed hyperreflective lesions on en face OCT images. 36.7±16.5% and 38.2±16.2% of microaneurysms on FA images were observed on OCTA and en face OCT images, respectively. The number of microaneurysms on either OCTA or OCT images were correlated to that on FA images (R=0.862, P<0.001). Additionally, the nonperfused areas on FA images corresponded almost to those on OCTA images, although en face OCT often detected capillaries in such areas. Further quantification showed that the areas of the FAZ on FA and OCTA images in the superficial layer were almost the same (intraclass correlation coefficient=0.984). The FAZs on en face OCT images were significantly smaller than those on OCTA images in both the superficial and deep layers (P<0.001 and P<0.001).
Conclusions :
The comparative study might show the structural-functional gap, i.e., vascular walls and blood flow, in retinal vasculature in DR, suggesting the feasibility of multi-modal evaluation of diabetic retinal vessels.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.