title: Quantification of plaque stiffness by Brillouin microscopy in experimental thin cap fibroatheroma.
abstract: Plaques vulnerable to rupture are characterized by a thin and stiff fibrous cap overlaying a soft lipid-rich necrotic core. The ability to measure local plaque stiffness directly to quantify plaque stress and predict rupture potential would be very attractive, but no current technology does so. This study seeks to validate the use of Brillouin microscopy to measure the Brillouin frequency shift, which is related to stiffness, within vulnerable plaques. The left carotid artery of an ApoE(-/-)mouse was instrumented with a cuff that induced vulnerable plaque development in nine weeks. Adjacent histological sections from the instrumented and control arteries were stained for either lipids or collagen content, or imaged with confocal Brillouin microscopy. Mean Brillouin frequency shift was 15.79 ± 0.09 GHz in the plaque compared with 16.24 ± 0.15 (p < 0.002) and 17.16 ± 0.56 GHz (p < 0.002) in the media of the diseased and control vessel sections, respectively. In addition, frequency shift exhibited a strong inverse correlation with lipid area of -0.67 ± 0.06 (p < 0.01) and strong direct correlation with collagen area of 0.71 ± 0.15 (p < 0.05). This is the first study, to the best of our knowledge, to apply Brillouin spectroscopy to quantify atherosclerotic plaque stiffness, which motivates combining this technology with intravascular imaging to improve detection of vulnerable plaques in patients.
authors.affiliation: Department of Physics, Imperial College London, London, UK Center for Life Nano Science, Istituto Italiano di Tecnologia, Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Antonacci
authors.affiliation: Department of Bioengineering, Imperial College London, London, UK.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Pedrigi
authors.affiliation: Department of Bioengineering, Imperial College London, London, UK.
authors.forename: Avinash
authors.initials: A
authors.lastname: Kondiboyina
authors.affiliation: Department of Bioengineering, Imperial College London, London, UK.
authors.forename: Vikram V
authors.initials: VV
authors.lastname: Mehta
authors.affiliation: National Heart and Lung Institute, Imperial College London, London, UK.
authors.forename: Ranil
authors.initials: R
authors.lastname: de Silva
authors.affiliation: Department of Physics, Imperial College London, London, UK.
authors.forename: Carl
authors.initials: C
authors.lastname: Paterson
authors.affiliation: Department of Bioengineering, Imperial College London, London, UK.
authors.forename: Rob
authors.initials: R
authors.lastname: Krams
authors.affiliation: Department of Physics, Imperial College London, London, UK peter.torok@imperial.ac.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Török
mesh_terms: D000818:Animals; D003094:Collagen / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D050356:Lipid Metabolism; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D058226:Plaque, Atherosclerotic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D059289:Vascular Stiffness
chemical_list: D003094:Collagen
keywords: atherosclerosis; biomechanics; plaque rupture