Multi-Center Repeatability of Macular Capillary Perfusion Density Using Optical Coherence Tomography Angiography

Area of Science:

• Ophthalmology
• Medical Imaging
• Cardiovascular Research

Background:

• Macular capillary perfusion density (CPD) is a key indicator of retinal health.
• Assessing CPD repeatability is crucial for clinical applications of OCTA.

Purpose of the Study:

• To evaluate the test-retest repeatability of macular CPD measurements using OCTA.
• To assess repeatability in a multi-center setting.

Main Methods:

• OCTA imaging was performed on healthy subjects at two centers (UM, UPenn).
• Macular CPD was quantified using fractal analysis (box-counting fractal dimension) of the superficial vascular plexus.
• Repeatability was assessed using within-subject standard deviation (Sw), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) for intra-visit and inter-visit measurements.

Main Results:

• OCTA-CPD demonstrated good to excellent intra-visit repeatability (Sw ≤0.004, CoVs ≤0.23%, ICCs ≥0.61) at both sites.
• Excellent inter-visit repeatability was also observed (Sw ≤0.005, CoVs ≤0.28%, ICCs ≥0.61).
• Bland-Altman analysis confirmed minimal bias and excellent agreement between repeated measurements.

Conclusions:

• High repeatability of OCTA-derived CPD can be achieved across different research sites.
• Standardized OCTA protocols and analysis enable consistent CPD quantification.