Attenuation correction assisted automatic segmentation for assessing choroidal thickness and vasculature with...

Area of Science:

• Ophthalmology
• Medical Imaging
• Biomedical Engineering

Background:

• Swept source optical coherence tomography (SS-OCT) offers deeper penetration and better image quality for choroidal investigation compared to spectral domain OCT.
• Current automatic methods for assessing choroidal thickness and vasculature using SS-OCT are limited in reliability and accuracy.

Purpose of the Study:

• To develop and validate an attenuation correction method for SS-OCT structural scans.
• To improve automatic segmentation of the choroid and enable visualization of choroidal vasculature.
• To assess the repeatability of choroidal thickness and vessel density measurements after correction.

Main Methods:

• Applied attenuation correction to SS-OCT structural scans.
• Developed an algorithm for automatic choroid segmentation on corrected B-scans.
• Visualized choroidal vasculature using corrected scans and compared segmentation accuracy with uncorrected scans.

Main Results:

• Attenuation correction significantly enhanced contrast at the choroidal-scleral interface (0.13 ± 0.05 to 0.29 ± 0.10; P < 0.001).
• The corrected segmentation algorithm achieved significantly higher accuracy (91.8 ± 3.7%) compared to automated segmentation on regular OCT scans (74.5 ± 8.0%; P < 0.01).
• Attenuation correction facilitated artifact-free visualization of choroidal vessels and demonstrated high repeatability for thickness and vessel density measurements.

Conclusions:

• Attenuation correction is a valuable method for improving SS-OCT based choroidal analysis.
• This approach enhances the accuracy of choroidal segmentation and the visualization of choroidal vasculature.
• The technique holds promise for quantitative studies in various chorioretinal diseases, including AMD and myopia.