Abstract
Purpose :
Widefield optical coherence tomography angiography (OCTA) has the potential to improve the detection of peripheral retinal lesions in diabetic retinopathy (DR) that might otherwise be missed using conventional OCTA scans. Widefield OCTA can be obtained by combining multiple cube scans taken at different locations. In this study we assessed a new volumetric montage protocol designed to cover an area of 24 mm (Horizontal) x 15 mm (Vertical) for the identification of peripheral vascular lesions.
Methods :
Ten eyes with diabetic retinopathy were imaged on PLEX® Elite 9000 swept-source OCT (ZEISS, Dublin, CA) by acquiring a central 15x15 mm angio scan of 17 um resolution followed by two lateral 15x15 mm angio scans at nasal and temporal fixations of same resolution as the central scan. The two lateral 15x15 mm angio scans were registered together such as to produce a volumetric 24 mm (H) x 15 mm (V) x 6mm (D) angio scan. The retinal slab from the resulting volumetric montage was compared to the retinal slab from the central single 15x15 mm scan to identify the extent of vascular lesion in the periphery.
Results :
Figure 1 and Figure 2 show the retinal slabs and central B-scans from the volumetric montage protocol and from central 15x15 mm angio scan respectively. Out of 10 eyes with diabetic retinopathy, 8 were found to have lesions beyond the central 15x15 mm FOV. In addition, the quality of the montage, especially over the overlapping area of the 2 scans was preserved with no noticeable artifact. The sampling resolution of the montage protocol of 17 um was found to be adequate to identify the type of lesions: ischemic area, microaneurysm, vessels tortuosity were commonly reported. Some of these lesions were also visible on the structural B-scan with flow signal overlaid.
Conclusions :
With a FOV of 24 mm (H) x 15 mm (V) and a sampling resolution of 17 um, the proposed volumetric montage protocol expands the imaging capability of OCTA for the detection and classification of vascular peripheral lesions.
This is a 2021 ARVO Annual Meeting abstract.