Swept-source optical coherence tomography angiography alleviates shadowing artifacts caused by subretinal fluid

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Diseases

Background:

• Choriocapillaris (CC) imaging is crucial for diagnosing retinal diseases.
• Subretinal fluid (SRF) can create artifacts in optical coherence tomography angiography (OCTA) analysis.
• Distinguishing true CC pathology from imaging artifacts is essential for accurate diagnosis.

Purpose of the Study:

• To compare the ability of spectral-domain OCTA (SD-OCTA) and swept-source OCTA (SS-OCTA) to characterize CC structure in the presence of SRF.
• To evaluate SRF as a source of systematic error in CC OCTA imaging.

Main Methods:

• Prospective case-control study involving 23 eyes (10 central serous chorioretinopathy, 3 retinal detachment, 10 controls).
• Quantitative comparison of CC decorrelation signals between patients and controls using custom image processing.
• Correlation of SRF extent (macular heatmap) with CC OCTA signal.

Main Results:

• SS-OCTA provided a more homogeneous CC OCTA signal with less variability than SD-OCTA.
• Both devices showed CC signal voids in diseased eyes, predominantly in areas with SRF.
• SS-OCTA reduced signal voids under SRF compared to SD-OCTA (7.6% vs. 19.7%), but voids persisted.

Conclusions:

• SRF is a significant artifact source in CC OCTA analysis due to shadowing.
• SS-OCTA mitigates but does not completely eliminate SRF-induced artifacts.
• Understanding these artifacts is critical for accurate clinical interpretation of CC OCTA.