Spectroscopic correlation tomography (SpCT) for visualization of spatial correlations in volumetric OCT scans

Area of Science:

• Biomedical Optics
• Medical Imaging
• Histopathology

Background:

• Spectroscopic Optical Coherence Tomography (SOCT) enables label-free analysis of cellular structures like nuclei.
• SOCT extracts structural and spectroscopic properties for optical biopsy applications.
• Spatial correlation analysis in SOCT can determine cell nucleus size and visualize tissue boundaries.

Purpose of the Study:

• Introduce Spectroscopic Correlation Tomography (SpCT) for enhanced OCT imaging.
• Develop a method to visualize spatial correlation changes in volumetric OCT data.
• Validate SpCT for accurate scatterer size quantification and tissue analysis.

Main Methods:

• Developed SpCT by mapping spatial correlation measurements to HSV color space.
• Acquired SpCT B-scans and volumes of polystyrene beads and fibroblast cells.
• Quantified scatterer sizes using Gaussian mixture models and connected component analysis.
• Compared SpCT with histology and confocal microscopy for validation.

Main Results:

• Achieved scatterer size estimates within half-wavelength accuracy using SpCT.
• Demonstrated strong agreement between SpCT and confocal microscopy for fibroblast nuclei.
• Successfully identified varying nuclear morphology in organoids and lung explants.
• Objectively discriminated between control and mutated colon organoids using SpCT volumes.

Conclusions:

• SpCT provides quantitative visualization of spatial correlations in OCT data.
• The technique accurately quantifies cell nuclei size and morphology.
• SpCT shows potential for label-free optical biopsy and clinical diagnostics.