Dynamic tissue analysis using time- and wavelength-resolved fluorescence spectroscopy for atherosclerosis diagnosis

Area of Science:

• Biomedical Optics
• Medical Diagnostics
• Fluorescence Spectroscopy

Background:

• Atherosclerosis diagnosis requires accurate tissue characterization.
• Current methods may lack real-time capabilities for dynamic assessment.
• Optical techniques offer potential for non-invasive analysis.

Purpose of the Study:

• To develop and validate Simultaneous Time- and Wavelength-Resolved Fluorescence Spectroscopy (STWRFS).
• To assess STWRFS for dynamic characterization of atherosclerotic tissue ex vivo and in vivo.
• To evaluate STWRFS for real-time optical characterization and atherosclerosis research.

Main Methods:

• Utilized a pulsed laser (337 nm, 700 ps) to induce autofluorescence.
• Employed dichroic filters to split fluorescence into three wavelength sub-bands.
• Used optical fibers for temporal separation and fast data acquisition (microseconds).
• Integrated a single-fiber probe with an ultrasound imaging catheter for in vivo studies.

Main Results:

• Successfully discriminated distinct compositions of human atherosclerotic aorta ex vivo.
• Discrimination was based on fluorescence lifetime and intensity ratios (390/452 nm).
• Validated STWRFS operation in pig femoral arteries in vivo.
• Demonstrated rapid scanning capabilities over several centimeters.

Conclusions:

• STWRFS is a promising tool for real-time optical characterization of arterial tissue.
• The technique shows potential for atherosclerosis research and diagnosis.
• STWRFS enables fast, detailed analysis of tissue composition.