Tissue characterization with depth-resolved attenuation coefficient and backscatter term in intravascular optical...

Area of Science:

• Biomedical Imaging
• Cardiovascular Research
• Optical Engineering

Background:

• Intravascular optical coherence tomography (IVOCT) is crucial for atherosclerotic tissue analysis.
• Estimating attenuation and backscatter coefficients is key for characterizing plaque composition.
• Current methods may lack precision in differentiating diverse tissue types within atherosclerotic plaques.

Purpose of the Study:

• To explore the potential of attenuation coefficient, a novel backscatter term, and image intensities in distinguishing atherosclerotic tissue types.
• To implement a robust depth-resolved (DR) approach for pixel-level estimation of these parameters.
• To develop an automated method for excluding noisy regions and accurately delineating tissue boundaries.

Main Methods:

• Introduced a depth-resolved (DR) model to estimate attenuation and backscatter coefficients in IVOCT images.
• Developed an automated algorithm to identify and exclude signal-weak, noisy regions.
• Analyzed local statistical values of attenuation coefficient, backscatter term, and image intensity in pathologically defined regions of interest.
• Utilized a two-sample t-test to compare distributions and evaluate tissue differentiation capabilities.

Main Results:

• The implemented DR model successfully estimated pixel-level attenuation and backscatter terms without prior delineation.
• An automated algorithm effectively determined cut-off borders, excluding noisy image regions.
• Analysis revealed that IVOCT intensity, DR attenuation coefficient, and backscatter term are complementary.
• These parameters demonstrated significant potential in characterizing six distinct tissue types: mixed, calcification, fibrous, lipid-rich, macrophages, and necrotic core.

Conclusions:

• The proposed DR model and associated parameters offer a robust method for detailed atherosclerotic plaque characterization using IVOCT.
• The complementary nature of intensity, attenuation, and backscatter enhances the ability to differentiate specific tissue components within plaques.
• This approach holds promise for improving diagnostic accuracy and guiding therapeutic strategies in cardiovascular disease.