Angle independent flow assessment with bidirectional Doppler optical coherence tomography

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• Bidirectional Doppler optical coherence tomography (BD-DOCT) accurately measures absolute blood flow velocity.
• BD-DOCT requires knowledge of the vessel's angle in the en face plane for accurate measurements.
• Existing methods face limitations due to the need for precise vessel orientation data.

Purpose of the Study:

• To develop an angle-independent method for calculating absolute blood flow velocity using BD-DOCT.
• To enhance the accuracy and flexibility of BD-DOCT techniques.
• To overcome the limitations of existing angle-dependent flow calculation methods.

Main Methods:

• Demonstrated a direct calculation of blood flow from BD-DOCT cross-sections.
• The calculation is performed perpendicular to the illumination plane.
• Validated the novel approach using in vitro experiments and in vivo human retinal vessel measurements.

Main Results:

• The direct calculation method is independent of the vessel angle and Doppler angle.
• Accurate blood flow values were obtained for most vascular plexuses.
• Precision decreased for larger en face angles, indicating practical limitations.

Conclusions:

• The angle-independent calculation significantly improves BD-DOCT accuracy and flexibility.
• This method allows for reliable blood flow assessment without precise knowledge of vessel orientation.
• The technique shows promise for broader applications in vascular imaging, despite limitations with large en face angles.