Abstract
Purpose :
To investigate the use of the new ultrawide-field en face swept-source optical coherence tomographic angiography (UWF-SS-OCTA) in the evaluation of microvascular changes in proliferative diabetic retinopathy (PDR) over the standard techniques of examination.
Methods :
A retrospective study including patients with PDR who underwent SS-OCTA imaging (PLEX® Elite 9000, Carl Zeiss Meditec, Inc.). Five 12x12 mm OCTA data cubes at different locations were acquired. UWF-OCTA en face montage was automatically generated with a total field of view up to 70 degree. Structural B-scan with overlaid flow signal, as well as the en face OCTA images of the superficial capillary plexus in each cube were analyzed. Areas of nonperfusion were graded on the en face OCTA. Neovascularization at the disc (NVD) and elsewhere (NVE) were identified as a preretinal hyperreflective material in the B scan(PRHM). Intraretinal microvascular abnormalities (IRMAs) were defined as abnormally dilated blood vessels on the en face OCTA, corresponding to intraretinal high flow signal in the B-scan. The findings from OCTA were compared to the available data collected from standard clinical examination, color fundus photography and ultrawide-field fluorescein angiography (UWF-FA, Optos 200TX)
Results :
Twenty-five eyes from 14 patients with PDR were included. Of all, 12 eyes had simultaneous UWF-FA. NVDs were detected in structural OCTA in 15 eyes; 60.0%( 9/15) had flow signal which might indicate activity, whereas on clinical examination NVDs were detected only in 40.0% (6/15). A total of 125 scans were analyzed for NVEs, which were detected in 60 scans (48.0%). Of these, 96.7% (58) demonstrated flow signals. IRMAs were detected in 18 scans (14.4%). Macular ischemia was graded from 0 to 4 based on foveal avascular zone disruption. The peripheral ischemia was graded depending on the number of retinal sectors involved, ranging from 1 to 5. In 100% of the eyes, at least 1 sector was involved, while in 56.0% of them, all the 5 sectors were involved. UWF-FA and UWF-OCTA were qualitatively comparable regarding the peripheral ischemia and new vessels detection. Although, UWF-FA had wider field, no clinically significant data was missed from UWF-OCTA
Conclusions :
UWF-OCTA accurately detected microvascular changes in PDR, which was comparable to UWF-FA in contrast to standard examination techniques
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.