Comparative study between swept-source and spectral-domain OCTA for imaging of choroidal neovascularization in...

To compare the differences of choroidal neovascularization (CNV) measurements between swept-source and spectral-domain optical coherence tomography angiography (SS-OCTA and SD-OCTA) in neovascular age-related macular degeneration (nAMD) and the imaging reliability of the two devices.

Prospective comparative study. SS-OCTA and SD-OCTA were used to scan the same eye with the modes of 3×3 and 6×6 mm² centered on the neovascularization. Only qualified images were chosen and the border of CNV was manually delineated by two graders independently. The area of CNV (ACNV), vascular perfusion density (PD), and vessel length density (VLD) within the delineation were calculated using Image J. The differences of CNV measurements between the two OCTA devices were compared using Bland-Altman analysis. The agreement between the two graders on the measurements of each device was compared using the intraclass correlation coefficient (ICC).

A total of 18 patients (22 eyes) with nAMD were included. The measurements of ACNV, PD, and VLD were 7.247±4.586 and 4.901±3.741 mm², 43.202±9.636 and 34.904±10.489, 6.339±1.228 and 5.908±1.741 mm^-1 for SS-OCTA and SD-OCTA, respectively. The differences between the two devices were 2.346±3.030 mm² (Z=-3.782, P<0.0001), 8.298±14.160 (Z=-2.419, P=0.016), and 0.431±2.114 mm^-1 (Z=-0.828, P=0.408) for ACNV, PD and VLD, respectively. The ICC between two graders were 0.893 (P<0.001), 0.902 (P<0.001), 0.885 (P<0.001) for ACNV, PD, VLD in SS-OCTA, and 0.971 (P<0.001), 0.976 (P<0.001), 0.973 (P<0.001) in SD-OCTA, respectively.

Both OCTA devices have high imaging reliability. Compared with SD-OCTA, SS-OCTA has a larger ACNV measurements, but doesn't show better resolution of internal vessels of CNV and well signal strength.