Reflection spectroscopy of atherosclerotic plaque

Area of Science:

• Cardiovascular Science
• Biomedical Optics
• Medical Diagnostics

Background:

• Heart disease remains a leading cause of mortality globally.
• Rupture of vulnerable plaques, characterized by large lipid cores and thin fibrous caps, is a primary driver of fatal cardiovascular events.
• Current detection methods for vulnerable plaques require further refinement for improved sensitivity and specificity.

Purpose of the Study:

• To analytically and quantitatively assess the sensitivity of reflection spectroscopy for detecting vulnerable plaques.
• To develop and validate a spectral measure of lipid content in atherosclerotic plaques.
• To compare spectral lipid content measurements with histological findings of lipid core thickness.

Main Methods:

• Reflection spectra were acquired from 77 measurement points across 23 human aortas in the 400–1700 nm range.
• A novel measure of plaque lipid content was derived from the reflectance spectra.
• Histological analysis determined lipid core thickness and fibrous cap thickness for comparison.

Main Results:

• The developed spectral measure demonstrated an 88% sensitivity and 94% specificity in detecting vulnerable plaques (lipid core >500 µm, fibrous cap <500 µm).
• The method accurately quantifies plaque lipid content.
• The sensitivity of reflection spectroscopy to fibrous cap thickness was limited.

Conclusions:

• Reflection spectroscopy is a promising tool for identifying lipid-rich plaques, a key characteristic of vulnerable cardiovascular disease.
• While effective for lipid content assessment, complementary modalities are needed to accurately measure fibrous cap thickness for comprehensive vulnerable plaque detection.