Comparison Between Spectral-Domain and Swept-Source Optical Coherence Tomography Angiographic Imaging of Choroidal Neovascularization

Abstract

PURPOSE. The purpose of this study was to compare imaging of choroidal neovascularization (CNV) using swept-source (SS) and spectral-domain (SD) optical coherence tomography angiography (OCTA). METHODS. Optical coherence tomography angiography was performed using a 100-kHz SS-OCT instrument and a 68-kHz SD-OCTA instrument (Carl Zeiss Meditec, Inc.). Both 3 x 3-and 6 x 6-mm(2) scans were obtained on both instruments. The 3 x 3-mm(2) SS-OCTA scans consisted of 300 A-scans per B-scan at 300 B-scan positions, and the SD-OCTA scans consisted of 245 A-scans at 245 B-scan positions. The 6 x 6-mm(2) SS-OCTA scans consisted of 420 A-scans per B-scan at 420 B-scan positions, and the SD-OCTA scans consisted of 350 A-scans and 350 B-scan positions. B-scans were repeated four times at each position in the 3 x 3-mm(2) scans and twice in the 6 x 6-mm(2) scans. Choroidal neovascularization was excluded if not fully contained within the 3 x 3-mm(2) scans. The same algorithm was used to detect CNV on both instruments. Two graders outlined the CNV, and the lesion areas were compared between instruments. RESULTS. Twenty-seven consecutive eyes from 23 patients were analyzed. For the 3 x 3-mm(2) scans, the mean lesion areas for the SS-OCTA and SD-OCTA instruments were 1.17 and 1.01 mm(2), respectively (P = 0.047). For the 6 x 6-mm(2) scans, the mean lesion areas for the SS-OCTA and SD-OCTA instruments were 1.24 and 0.74 mm(2) (P = 0.003). CONCLUSIONS. The areas of CNV tended to be larger when imaged with SS-OCTA than with SD-OCTA, and this difference was greater for the 6 x 6-mm(2) scans.