Impact of image averaging on choroidal quantification using swept-source optical coherence tomography

This study aimed to assess the impact of B-scan averaging on choroidal parameters using swept-source optical coherence tomography (SS-OCT).

Twenty-two right eyes of healthy adults were scanned using SS-OCT. Each scan included five consecutive 9 mm 18-line radial scans with averaging frames of 4, 8, 16, 32, and 64. Two times of averaging were performed per eye. Choroidal images were analyzed with binarization techniques to calculate choroidal parameters, including luminal volume (LV), stromal volume (SV), choroidal vascularity index (CVI), total choroidal volume (TCV), and choroidal thickness (CT), to compare the changes and stability of these parameters under different B-scans averaging conditions.

CVI showed no significant differences across averaging conditions (P > 0.05), while LV, SV, TCV, and CT differed significantly (P < 0.05). LV, TCV, and CT showed no significant differences when averaging ≥ 16 frames, whereas SV achieved stability at ≥ 8 frames.

This study demonstrated that SS-OCT imaging of the choroid was unaffected by B-scan averaging in CVI measurements. However, LV, TCV, and CT required averaging ≥ 16 frames, while SV required averaging ≥ 8 frames for consistent results. This finding emphasizes the importance of standardized imaging protocols in clinical practice.