Phase-restoring subpixel image registration: enhancing motion detection performance in Fourier-domain optical...

Area of Science:

• Biomedical Optics
• Medical Imaging
• Ophthalmology

Background:

• Phase-sensitive Fourier-domain optical coherence tomography (FD-OCT) allows label-free, in vivo imaging of cellular dynamics with nanometer sensitivity.
• Functional imaging modalities like optoretinography (ORG), Doppler OCT, and optical coherence elastography utilize FD-OCT for cellular movement detection.
• Inter-frame displacement in in vivo FD-OCT imaging introduces decorrelation noise, degrading motion detection sensitivity and accuracy.

Purpose of the Study:

• To develop and validate a method for correcting displacement-related decorrelation noise in FD-OCT.
• To enhance the sensitivity and accuracy of in vivo cellular motion detection using FD-OCT.
• To restore the phase information compromised by motion artifacts in OCT imaging.

Main Methods:

• Proposed a novel Phase-Restoring Subpixel Image Registration (PRESIR) method based on a general FD-OCT model.
• PRESIR enables subpixel precision translational shifting of complex-valued OCT images while preserving phase information.
• The method corrects axial displacement in the spectral (k) domain and lateral displacement in the spatial frequency domain.

Main Results:

• The PRESIR method effectively corrected displacement-related decorrelation noise in FD-OCT.
• Simulations, phantom experiments, and in vivo optoretinography (ORG) in rodents and humans validated the method's performance.
• Achieved phase sensitivity close to the theoretical limit defined by signal-to-noise ratio, significantly reducing noise in moving samples.

Conclusions:

• The PRESIR method provides accurate correction of motion artifacts in FD-OCT imaging.
• This technique significantly improves the sensitivity and accuracy of in vivo cellular motion detection.
• PRESIR advances functional imaging modalities relying on precise phase measurements in dynamic biological tissues.