Image inversion spectral-domain optical coherence tomography optimizes choroidal thickness and detail through...

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Imaging

Background:

• Accurate visualization of choroidal structures is crucial for diagnosing and monitoring various ocular diseases.
• Spectral-domain optical coherence tomography (SD-OCT) is a key technology for in-vivo imaging of the choroid.
• Image acquisition parameters, such as inversion, can potentially influence the quality of SD-OCT images.

Purpose of the Study:

• To compare choroidal thickness, contrast, outer choroidal vessel (OCV), and choroidal-scleral junction (CSJ) visualization between inverted and upright SD-OCT imaging.
• To evaluate the performance of different SD-OCT devices (Bioptigen, Zeiss Cirrus, Heidelberg Spectralis) in capturing these parameters.

Main Methods:

• SD-OCT images were acquired from 42 eyes of 21 healthy subjects using Bioptigen, Zeiss Cirrus, and Heidelberg Spectralis devices.
• Choroidal thickness was measured using MATLAB, while contrast and CSJ visualization were quantitatively and qualitatively assessed.
• Outer choroidal vessels (≥ 200 μm) were counted to determine OCV.

Main Results:

• Inverted SD-OCT imaging resulted in significantly greater mean choroidal thickness with Bioptigen and Spectralis devices.
• Higher contrast was observed in inverted images from Bioptigen and Spectralis, but not from Cirrus.
• The Spectralis inverted and EDI modes, along with Cirrus upright and Bioptigen inverted, showed the highest CSJ visualization scores, with Spectralis inverted also yielding the highest OCV.

Conclusions:

• Specific inverted and upright modes on Spectralis, Cirrus, and Bioptigen SD-OCT devices provide optimal visualization of the choroidal-scleral junction (CSJ) and outer choroidal vessels (OCV).
• These superior modes also demonstrate enhanced outer choroidal contrast and choroidal thickness measurements.
• Differences in conversion factors preclude direct comparison of choroidal thickness measurements across different SD-OCT machines.