The effect of increasing A-scan rate on OCTA images: A qualitative and quantitative analysis

Author: Rosa Dolz-Marco (Spain)

Co-authors: Javier Muñoz-Solano, Robert Montés-Micó, Roberto Gallego-Pinazo

Purpose

To evaluate the effect of A-scan rate increase on qualitative and quantitative parameters in optical coherence tomography angiography (OCTA) images as well as the quantitative data agreement.

Setting/Venue

Oftalvist Clinic, Valencia, Spain

Methods

Healthy individuals undergoing comprehensive ophthalmic examination were scheduled for OCTA imaging using a modified SPECTRALIS device allowing for 85.000 and 125.000 A-scans/second. Consecutive, registered, 20ºx20º OCTA images using both speeds were acquired using the follow-up tool. The quality values of each B-scan were extracted and analyzed. The image quality was also qualitatively and blindly graded in pairs of images with different speeds. It was assessed if they were equal, or one was better than the other or even meaningfully better so the other was not usable. Vascular densities were calculated and the agreement between OCTA pairs was also assessed.

Results

Fifty-four eyes of 54 patients (35 female, mean age 64.6 years) were included in the present study. A significant reduction in the acquisition time was achieved with no significant differences in the Q values of the OCTA scans or in the qualitative blind assessment and vascular density values.

Conlusions

The benefit of speed on OCTA imaging is well stablished. Higher scan rates improve workflow, but also reduce image sensitivity and image quality might be compromised. In the present study, 125.000 A-scan rate showed benefit with a significant reduction on the acquisition time with no significant clinical differences between scan pairs. Further studies with different devices are required to confirm these results.

Financial Disclosure

We have research support by Heidelberg Engineering provided to the clinic with the possibility to use the prototype described in the present abstract.