Abstract 14124: Catheter-Based Technology for Label-Free Simultaneous Biochemical and Structural Imaging of Atherosclerotic Plaques: Development and Validation in Human Coronary Arteries
Introduction: Atherosclerosis research and diagnosis requires new techniques capable of evaluating, in patients, changes in plaque biochemical features that related to the underlying structure. We report a unique rotational catheter-based system combining multispectral fluorescence lifetime imaging (FLIM) with intravascular ultrasound (IVUS) for label-free simultaneous assessment of plaque composition and microanatomy. We hypothesized that FLIM has the potential to complement conventional IVUS images by providing complementary biochemical information on lipid-rich regions and inflammatory activity in the intima without the use of contrast agents.
Methods: A catheter combining a rotational 300 microns side-viewing fiberoptic and a 3 Fr IVUS transducer (40 MHz) was engineered and coupled to FLIM and IVUS instrumentation, respectively, and used to measure coronary segments (pullback at 2 mm/sec) from 5 human hearts. Tissue autofluorescence was measured in wavelength bands corresponding to the emission of collagen, elastin, and lipids. FLIM parameters (intensity, lifetimes values) and IVUS (grey-scale images) derived from bimodal measurements were evaluated and validated by tissue histopathology (H&E, trichrome, CD45, CD68.).
Results: Tissue regions with different pathologies showed distinct FLIM features. For example, the fluorescence lifetime (452±22 nm spectral band) was different (p<0.01) between regions with pathological intimal thickening (3.78±0.04 ns), thick cap fibroatheromas (3.92±0.21 ns) and fibroatheromas with high macrophage and T-lymphocyte infiltration in the fibrotic cap (3.63±0.14 ns). Angular co-registration of FLIM (lumen surface) with IVUS images demonstrated synchronous visualization of biochemical and structural features of the artery (Figure).
Conclusion: FLIM co-registered with IVUS improves the characterization of plaque composition and has high potential for atherosclerosis research and diagnosis.
- Interventional cardiology
- Cardiovascular imaging
- Vulnerable plaque
- Intravascular ultrasound/Doppler
- © 2013 by American Heart Association, Inc.