Detection of rupture-prone atherosclerotic plaques by time-resolved laser-induced fluorescence spectroscopy

Atherosclerosis. 2009 May;204(1):156-64. doi: 10.1016/j.atherosclerosis.2008.08.035. Epub 2008 Sep 6.

Abstract

Objective: Plaque with dense inflammatory cells, including macrophages, thin fibrous cap and superficial necrotic/lipid core is thought to be prone-to-rupture. We report a time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) technique for detection of such markers of plaque vulnerability in human plaques.

Methods: The autofluorescence of carotid plaques (65 endarterectomy patients) induced by a pulsed laser (337 nm, 0.7 ns) was measured from 831 distinct areas. The emission was resolved spectrally (360-550 nm range) and temporally (0.3 ns resolution) using a prototype fiber-optic TR-LIFS apparatus. Lesions were evaluated microscopically and quantified as to the % of different components (fibrous cap, necrotic core, inflammatory cells, foam cells, mature and degraded collagen, elastic fibers, calcification, and smooth muscle cell of the vessel wall).

Results: We determined that the spectral intensities and time-dependent parameters at discrete emission wavelengths (1) allow for discrimination (sensitivity >81%, specificity >94%) of various compositional and pathological features associated with plaque vulnerability including infiltration of macrophages into intima and necrotic/lipid core under a thin fibrous cap, and (2) show a linear correlation with plaque biochemical content: elastin (P<0.008), collagen (P<0.02), inflammatory cells (P<0.003), necrosis (P<0.004).

Conclusion: Our results demonstrate the feasibility of TR-LIFS as a method for the identification of markers of plaque vulnerability. Current findings enable future development of TR-LIFS-based clinical devices for rapid investigation of atherosclerotic plaques and detection of those at high-risk.

Publication types

  • Research Support, N.I.H., Extramural
  • Validation Study

MeSH terms

  • Calcinosis / pathology
  • Carotid Artery Diseases / metabolism
  • Carotid Artery Diseases / pathology*
  • Carotid Artery Diseases / surgery
  • Carotid Artery, Common / chemistry
  • Carotid Artery, Common / pathology*
  • Carotid Artery, Common / surgery
  • Collagen / analysis
  • Elastin / analysis
  • Endarterectomy, Carotid
  • Feasibility Studies
  • Fiber Optic Technology*
  • Fibrosis
  • Foam Cells / pathology
  • Humans
  • Lasers*
  • Lipids / analysis
  • Necrosis
  • Predictive Value of Tests
  • Reproducibility of Results
  • Rupture
  • Sensitivity and Specificity
  • Spectrometry, Fluorescence / methods*
  • Time Factors

Substances

  • Lipids
  • Collagen
  • Elastin