Correcting for sub-resolution tissue motion in localization optoacoustic tomography.

Area of Science:

• Biomedical Imaging
• Optics and Photonics
• Medical Physics

Background:

• Localization optoacoustic tomography (LOT) offers high spatial resolution in optoacoustic imaging, surpassing the acoustic diffraction limit.
• LOT enables quantitative blood flow velocity measurements by tracking absorbing particles.
• Physiological motion and inter-frame displacements significantly degrade LOT resolution and hinder accurate velocity quantification.

Purpose of the Study:

• To develop and validate a motion correction method for localization optoacoustic tomography (LOT).
• To improve particle tracking and blood flow velocity measurements in the presence of physiological motion.
• To enhance the robustness and accuracy of LOT for in vivo imaging applications.

Main Methods:

• A geometric-transformation-based approach using singular value decomposition (SVD) for frame alignment.
• SVD clutter filter to separate static background (blood vessels) from dynamic flowing particles.
• Motion estimation performed on the background sequence, followed by correction of the particle sequence.

Main Results:

• Successful alignment of motion-affected LOT frames to a reference frame.
• Demonstrated improvement in particle tracking and localization accuracy post-motion correction.
• Enhanced performance validated in phantom experiments and in vivo mouse brain LOT imaging.

Conclusions:

• The proposed geometric-transformation and SVD-based method effectively corrects for physiological motion in LOT.
• This approach significantly enhances the reliability of blood flow velocity measurements using LOT.
• The technique holds promise for improving high-resolution in vivo optoacoustic imaging.