Optical coherence tomography angiography analysis methods: a systematic review and meta-analysis.

Area of Science:

• Ophthalmology
• Medical Imaging
• Vascular Biology

Background:

• Optical coherence tomography angiography (OCTA) is a key non-invasive tool for retinal vascular imaging.
• Current OCTA methodologies for assessing retinal perfusion exhibit considerable variation across studies.
• This variability complicates the interpretation and comparison of research findings.

Purpose of the Study:

• To systematically evaluate and characterize the diverse methods used for assessing retinal perfusion in OCTA studies.
• To identify the extent of heterogeneity in OCTA techniques employed in retinal vascular imaging.
• To provide evidence supporting the need for standardization in OCTA methodology.

Main Methods:

• A comprehensive literature search of MEDLINE and Embase databases from 2014 to August 2021 was conducted.
• Prospective studies with ≥50 participants using OCTA for retinal perfusion assessment in global retinal or systemic disorders were included.
• Risk of bias and data heterogeneity were assessed using established statistical tools and quality assessment frameworks.

Main Results:

• Out of 5974 identified studies, 191 were included, revealing 197 distinct methods for assessing macula perfusion, arising from combinations of devices, volume dimensions, subregions, analyses, and vessel layers.
• Meta-analysis of 88 studies showed reduced retinal perfusion in diabetes mellitus patients compared to controls, albeit with high heterogeneity.
• Heterogeneity was lowest and vascular effects most pronounced when assessing the superficial capillary plexus.

Conclusions:

• Systematic review demonstrates massive heterogeneity in OCTA methods for retinal perfusion assessment.
• The findings strongly support the urgent need for standardization of OCTA methodologies to improve research consistency and clinical applicability.
• Standardized OCTA protocols are crucial for reliable retinal vascular imaging and accurate assessment of perfusion in various ocular and systemic conditions.