Widefield swept-source optical coherence tomography angiography (SS-OCT-A) can provide imaging relevant to retinal vein occlusion (RVO) lesions that is similar — or, potentially, superior — to ultra-widefield fundus fluorescein angiography (UWF-FA), according to research published in BMC Ophthalmology. The study shows the technology’s strengths in monitoring the foveal avascular zone (FAZ), nonperfusion areas (NPA), capillary changes, and collateral vessels (except for microaneurysms [MAs]) and suggests that widefield SS-OCT-A is the more efficient approach to diagnosing and monitoring RVO.
The investigation enrolled 34 eyes of 32 patients (mean age, 56.3±14.4 years; 17 men, 15 women) with treatment-naïve RVO who visited Peking University People’s Hospital from September 2021 to March 2022. Patients underwent a comprehensive ophthalmic examination including imaging with a UWF-FA (200°) and a widefield SS-OCT-A utilizing 24×20 mm scan single capture. The team performed quantitative assessments of RVO lesions including FAZ area and perimeter, NPA, number of MAs, capillary changes and collateral vessels.
Investigators found no significant difference in FAZ area and perimeter between SS-OCT-A and UWF-FA images (P =.818 and P =.536, respectively). Intraclass correlation coefficients (ICCs) in FAZ area and perimeter between SS-OCT-A and UWF-FA was high (0.999, [0.997–0.999] and 0.996 [0.991–0.996], respectively), suggesting good agreement between the 2 imaging methods.
The average NPA area was larger on SS-OCT-A than on UWF-FA (89.977±78.805 mm2 vs 87.944±77.444 mm2, P =.037), and the ICC of NPA area was also high (0.999, [0.999–1.000]), according to the report. The median of total MA count was less on SS-OCT-A than on UWF-FA (7 [range, 0–19] vs 12 [range, 0–23], P <.001), the report shows.
The team found good agreement in identifying MAs between SS-OCT-A and UWF-FA (ICC=0.920, [0.555–0.974]). The total capillary changes and collateral vessels count was less on UWF-FA compared with SS-OCT-A (11±9 vs 6±7, P <.001 and 4 [range, 0–6] vs 0 [range, 0–0], P <.001, respectively). The team found fair agreement in identifying capillary changes and collateral vessels between OCT-A and UWF-FA (ICC=0.733, [0.081–0.905] and 0.564, [0.039–0.805], respectively).
Previous research suggests that large or progressive NPAs can be a biomarker of disease progression or regression, potentially informing management and treatment decisions.
“Our results suggested that the NPA on SS-OCT-A images were slightly larger than that on UWF-FA, which was consistent with previous investigations. This difference can be explained by no interference of fluorescence leakage on OCT-A due to a high resolution of vascular network in macular images on OCT-A. Moreover, blockages of fluorescence due to retinal hemorrhage on FA can be avoided on OCT-A images due to its long wavelength,” the researchers report.
Study limitations include its cross-sectional design, limited sample size, only Chinese patients were included, and possibility of measurement bias due to the manual segmentation and annotation methods.
Siying L, Qiaozhu Z, Xinyao H, Linqi Z, Mingwei Z, Jinfeng Q. Comparison of widefield swept-source optical coherence tomography angiography with ultra-widefield fluorescein angiography for the evaluation of lesions in retinal vein occlusion. BMC Ophthalmol. Published online November 7, 2022. doi:10.1186/s12886-022-02642-1