Refractive errors and corrections for OCT images in an inflated lung phantom

Area of Science:

• Pulmonary imaging and respiratory mechanics.
• Biomedical optics and instrumentation.
• Quantitative microscopy and image analysis.

Background:

• Accurate assessment of alveolar volume is vital for understanding respiratory mechanics.
• Optical Coherence Tomography (OCT) offers real-time imaging of lung tissue but suffers from optical artifacts.
• Existing methods lack 'ground truth' for analyzing and correcting these OCT-induced errors in lung imaging.

Purpose of the Study:

• To develop a method for analyzing and correcting optical artifacts in Optical Coherence Tomography (OCT) imaging of lung tissue.
• To establish a reliable 'ground truth' for validating OCT measurements of alveolar volume.
• To improve the accuracy of alveolar volume assessment for respiratory mechanics studies.

Main Methods:

• Adapted the Bragg-Nye bubble raft as a lung phantom with geometries similar to alveoli.
• Applied exact optical ray tracing on OCT images of the bubble raft to predict and correct optical errors.
• Validated OCT results by comparing them with transillumination imaging using a charged coupled device (CCD) camera.

Main Results:

• Developed a lung phantom (Bragg-Nye bubble raft) to simulate alveolar structures and their optical properties.
• Successfully predicted and corrected optical artifacts in OCT images using optical ray tracing.
• Validated the accuracy of the corrected OCT measurements against a CCD camera 'ground truth'.

Conclusions:

• The Bragg-Nye bubble raft serves as an effective phantom for analyzing OCT optical artifacts in lung imaging.
• Optical ray tracing can accurately predict and correct refractive errors in OCT measurements of alveolar structures.
• This approach enhances the reliability of OCT for quantitative assessment of alveolar volume and respiratory mechanics.