Abstract
Purpose :
To quantify relative blood flow velocity in macular neovascular vessels (MNV) in neovascular age-related macular degeneration (nAMD) using swept source optical coherence tomography angiography (SS-OCTA) and variable interscan time analysis (VISTA).
Methods :
OCTA imaging was performed using a high-speed 400 kHz SS-OCT prototype (Topcon Corp., Tokyo, Japan) for 4 eyes of 4 patients: MNV type 1, type 1+2, type 3, and PCV, immediately after anti-vascular endothelial growth factor (VEGF) treatment. The prototype device uses a unique scanning pattern that combines high-speed circle fast-scan and low-speed spiral slow-scan to image a 7 mm diameter area centered at the macula. Three-dimensional eye-motion correction processing was applied in the post-processing using the redundancy of the scan. In addition to the OCTA image, the saturation time of OCTA signal was calculated using the VISTA method to generate a relative blood flow velocity image. OCTA image from outer retina was extracted and a region of interest (ROI) was set for MNV area. Relative blood flow velocity in the ROI was calculated as a function of vessel diameter.
Results :
By introducing a novel scanning method, the prototype device was able to obtain OCTA and VISTA images without significant motion artifacts. The relative flow velocity within an ROI around the MNV is summarized in Table 1 except for the type 3 MNV case, where neovascularity runs longitudinally against retina and OCTA/VISTA is not suitable. Blood flow velocity was found to be slower in the smaller vessels for all cases.
Conclusions :
This study made it possible to visualize the blood flow velocity according to the diameter of the blood vessels that forms MNV. Blood flow analysis using this method is expected to contribute to the diagnosis of AMD and to study their treatment efficacy.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.