Reproducibility of Macular Vessel Density Calculations Via Imaging With Two Different Swept-Source Optical Coherence...

Area of Science:

• Ophthalmology
• Medical Imaging
• Biomedical Engineering

Background:

• Optical coherence tomography angiography (OCTA) is crucial for visualizing retinal vasculature.
• Swept-source OCTA (SS-OCTA) offers enhanced penetration and speed for OCTA imaging.
• Standardized vessel density calculations are essential for clinical applications.

Purpose of the Study:

• To compare the reproducibility of vessel density measurements between two commercial SS-OCTA systems (PLEXElite and Triton).
• To evaluate the impact of different binarization methods on vessel density reproducibility.
• To assess image quality and identify factors affecting measurement reliability.

Main Methods:

• Two SS-OCTA devices (PLEXElite and Triton) were used to image healthy volunteers' maculae.
• A 3x3mm volume scan pattern centered on the fovea was employed.
• Six binarization methods (two global, four local adaptive) in ImageJ were applied to calculate vessel density.
• Sixty eyes from 30 healthy subjects were analyzed by two masked reviewers.

Main Results:

• Twenty-two eyes were excluded due to poor image quality, with Triton showing significantly more exclusions (P=0.003).
• Local adaptive thresholding methods yielded higher reproducibility than global thresholding for both devices.
• Coefficients of variation for vessel density ranged from 0.3% to 2.3% for PLEXElite and 0.6% to 4.7% for Triton.

Conclusions:

• Both SS-OCTA instruments demonstrated good reproducibility for macular vessel density measurements.
• PLEXElite exhibited better performance with fewer excluded images and higher reproducibility than Triton.
• These findings aid in selecting appropriate binarization techniques for detecting retinal vascular diseases.