Abstract
Purpose :
To compare the detection rate of microvascular lesions between an ultrafast Megahertz widefield optical coherence tomography angiography (MHz WF-OCTA) device and commercially available WF-OCTA, fluorescein angiography (FA) and color fundus (CF) imaging.
Methods :
For this cross-sectional study, diabetic patients with diabetic retinopathy (DR) were recruited at the Department of Ophthalmology at the Medical University of Vienna. MHz WF-OCTA 3D data were acquired with a custom-built swept-source (SS) OCT prototype (A-scan rate: 1.7MHz; FOV: 18mm in diameter) and further processed with deep learning (DL) based 3D denoising. Corresponding images were obtained with PLEX® Elite 9000 (ZEISS, Dublin, CA; A-scan rate: 200 kHz; FOV: 12x12mm) and Optos® California (Optos; FA and CF imaging). Microaneurysms (MAs) and intraretinal microvascular abnormalities (IRMAs) were evaluated on en face OCTA/FA/CF images within an extended ETDRS grid consisting of a central 1 mm diameter disc, inner (0.5–1.5mm), outer (1.5–3.0mm) and extended ring (3.0-6.0mm).
Results :
Thirty-four eyes of 34 patients with severe non-proliferative DR (n=11) and proliferative DR (n=23) were included. A mean number of 160 ± 145 (± standard deviation) MAs per eye were detected manually by a clinician from the gold standard FA images. MHz WF-OCTA, WF-OCTA and CF imaging detected 55%, 44% and 34% of MAs, respectively. Significantly more MAs in total were detected on MHz WF-OCTA compared to WF-OCTA (p=0.007). Both OCTA devices detected IRMAs in all 34 eyes. Rate of IRMA detection was higher in the inner and outer ring using MHz WF-OCTA compared to WF-OCTA (47% vs. 24% and 91% vs. 65%, respectively). MHz WF-OCTA outperformed FA in IRMA detection in the inner (47% vs. 26%), outer (91% vs. 71%) and extended ring (100% vs. 97%). In one eye (3%) on FA and in six eyes (18%) on CF, no IRMAs were visible. There were no eyes presenting with IRMAs in the central 1 mm in any of the imaging modalities. Details of MA and IRMA detection rates with different imaging modalities in specific ETDRS rings are shown in Table 1.
Conclusions :
MHz WF-OCTA imaging in combination with DL based image quality improvement techniques show accurate performance in MA detection and outperforms FA in the detection of IRMAs in advanced stages of DR, potentially simplifying correct DR staging and disease monitoring in diabetic patients.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.