Frequency-doubled alexandrite laser for tissue differentiation in angioplasty

M. Scheu; Ralf Engelhardt

doi:10.1117/12.44029

1 May 1991 Frequency-doubled alexandrite laser for tissue differentiation in angioplasty

M. Scheu, Ralf Engelhardt

Proceedings Volume 1425, Diagnostic and Therapeutic Cardiovascular Interventions; (1991) https://doi.org/10.1117/12.44029
Event: Optics, Electro-Optics, and Laser Applications in Science and Engineering, 1991, Los Angeles, CA, United States

Abstract

The Q-switched Alexandrite laser (750 nm/375 nm; 150 ns-2microsecond(s) ) may be a solid-state alternative to excimer and pulsed dye lasers in laser angioplasty. The aim of this study was to determine whether laser induced fluorescence spectroscopy performed at 375 nm excitation could guide an Alexandrite laser angioplasty system. Thirty three segments of femoral arteries - classified as normal aorta, yellow fatty atheroma, and calcified plaque - were irradiated at a fluence of 0.2 J/cm² and investigated spectroscopically in vitro. Calcified plaque and normal aortic LIF spectra showed a fluorescence peak at 450 nm, yellow fatty plaque spectra revealed an additional peak of equal or lower intensity at 520 nm. The ratio of the laser-induced fluorescence intensity at 465 nm and 530 nm was used to discriminate yellow fatty atheroma from normal artery wall. This fluorescence intensity ratio was 2.55+/- 0.25 for normal aorta, 2.35+/- 0.33 for calcified plaque, and 1.42+/- 0.27 for yellow fatty plaque, respectively. Using a discrimination threshold of 2.0, 95% of the yellow fatty plaque could be classified correctly. Thrombs showed no fluorescence signal. An Alexandrite laser system might allow the simultaneous ablation and identification of vascular tissue in laser angioplasty.

Citation Download Citation

M. Scheu and Ralf Engelhardt "Frequency-doubled alexandrite laser for tissue differentiation in angioplasty", Proc. SPIE 1425, Diagnostic and Therapeutic Cardiovascular Interventions, (1 May 1991); https://doi.org/10.1117/12.44029

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