Parabolic BM-scan technique for full range Doppler spectral domain optical coherence tomography

Area of Science:

• Biomedical Optics
• Ophthalmology
• Medical Imaging

Background:

• Spectral domain optical coherence tomography (SD-OCT) is widely used for imaging.
• Standard linear phase modulation in SD-OCT struggles with mirror image elimination in samples with high axial motion.
• This limitation affects the accuracy of Doppler imaging, particularly for moving structures.

Purpose of the Study:

• To introduce and evaluate a novel parabolic phase modulation technique for SD-OCT.
• To overcome the limitations of linear phase modulation in mirror image elimination.
• To improve the velocity range and accuracy of phase-resolved Doppler imaging.

Main Methods:

• A parabolic phase modulation pattern was applied to the SD-OCT reference beam using an electro-optic modulator.
• The technique was tested using flow phantom experiments and in vivo imaging.
• Performance was compared against the standard linear phase modulation method.

Main Results:

• The parabolic phase modulation technique demonstrated superior mirror image elimination compared to linear modulation for structures with high velocities.
• Enhanced mirror image removal directly led to an improved velocity range in phase-resolved Doppler imaging.
• Flow phantom and in vivo results confirmed the effectiveness of the proposed method.

Conclusions:

• Parabolic phase modulation is an effective strategy to enhance mirror image elimination in SD-OCT.
• This technique improves the accuracy of Doppler imaging, especially for dynamic biological samples.
• The method holds significant potential for advanced retinal blood flow measurements in ophthalmologic diagnosis.