Elastographic mapping in optical coherence tomography using an unconventional approach based on correlation...

Area of Science:

• Biomedical Optics
• Medical Imaging
• Biophysics

Background:

• Optical coherence tomography (OCT) is a non-invasive imaging modality.
• Elastography aims to map tissue mechanical properties.
• Existing OCT elastography methods often rely on complex displacement calculations.

Purpose of the Study:

• To develop and validate a new OCT elastography approach based on correlation stability.
• To enable quantitative mapping of relative tissue stiffness.
• To overcome limitations of existing OCT elastography techniques.

Main Methods:

• Utilizing the comparison of correlation stability of sequentially obtained OCT images under strain.
• Implementing a sliding correlation window to compensate for translational motion.
• Analyzing image distortion to infer relative tissue stiffness, avoiding numerical differentiation of displacements.
• Employing either morphological features or speckle-level cross-correlation for analysis.

Main Results:

• Demonstrated that stiffer tissues exhibit less image distortion, leading to higher correlation stability.
• Showcased the ability to map relative tissue stiffness distribution.
• Validated the approach through numerical simulations and experimental data from phantoms and in vivo OCT images.
• Highlighted a wider strain range of operability compared to displacement-based methods.

Conclusions:

• The correlation stability (CS) approach provides a robust method for OCT elastography.
• This technique simplifies the process by eliminating the need for local strain reconstruction.
• The CS method is suitable for free-hand implementation and offers improved performance for softer tissues.