Scan speed affects quantitative optical coherence tomography angiography vascular metrics

Area of Science:

• Ophthalmology
• Medical Imaging
• Biomedical Engineering

Background:

• Optical coherence tomography angiography (OCTA) is crucial for quantifying retinal vasculature, serving as a biomarker for various diseases.
• Variations in OCTA manufacturer and scan settings can impact vessel quantification accuracy.
• Understanding these technical influences is vital for reliable OCTA-based diagnostics.

Purpose of the Study:

• To investigate the impact of different scan speeds on quantitative vascular parameters obtained via OCTA.
• To assess how scan speed affects vessel density (VD) and vessel length density (VLD) in retinal vascular plexuses.

Main Methods:

• 57 healthy eyes underwent OCTA imaging using the SPECTRALIS SHIFT system.
• Two consecutive 20x20° macular scans were performed at 85 kHz and 125 kHz.
• Vessel density (VD) and vessel length density (VLD) were compared between the two scan speeds, along with scan duration and Q-value.

Main Results:

• OCTA scans at 85 kHz yielded significantly higher VD and VLD values compared to 125 kHz scans.
• The reduction in VD and VLD at 125 kHz ranged from 3.35% to 6.66% across different plexuses.
• Acquisition time decreased by 22% at 125 kHz, but image quality (Q-value) was lower (34.1 vs. 35.6).

Conclusions:

• Increased OCTA scan speed (125 kHz vs. 85 kHz) reduces scan time but leads to an underestimation of retinal vascular metrics.
• These findings highlight the importance of standardized scan settings for consistent OCTA analysis.
• Further research is needed to quantify these effects in eyes with ocular pathologies.