title: Quantitative "magnetic resonance immunohistochemistry" with ligand-targeted (19)F nanoparticles.
abstract: Unstable atherosclerotic plaques exhibit microdeposits of fibrin that may indicate the potential for a future rupture. However, current methods for evaluating the stage of an atherosclerotic lesion only involve characterizing the level of vessel stenosis, without delineating which lesions are beginning to rupture. Previous work has shown that fibrin-targeted, liquid perfluorocarbon nanoparticles, which carry a high payload of gadolinium, have a high sensitivity and specificity for detecting fibrin with clinical (1)H MRI. In this work, the perfluorocarbon content of the targeted nanoparticles is exploited for the purposes of (19)F imaging and spectroscopy to demonstrate a method for quantifiable molecular imaging of fibrin in vitro at 4.7 T. Additionally, the quantity of bound nanoparticles formulated with different perfluorocarbon species was calculated using spectroscopy. Results indicate that the high degree of nanoparticle binding to fibrin clots and the lack of background (19)F signal allow accurate quantification using spectroscopy at 4.7 T, as corroborated with proton relaxation rate measurements at 1.5 T and trace element (gadolinium) analysis. Finally, the extension of these techniques to a clinically relevant application, the evaluation of the fibrin burden within an ex vivo human carotid endarterectomy sample, demonstrates the potential use of these particles for uniquely identifying unstable atherosclerotic lesions in vivo.
authors.affiliation: Department of Medicine, Washington University, Saint Louis, Missouri 63110, USA.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Morawski
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Winter
authors.forename: Xin
authors.initials: X
authors.lastname: Yu
authors.forename: Ralph W
authors.initials: RW
authors.lastname: Fuhrhop
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Scott
authors.forename: Franklin
authors.initials: F
authors.lastname: Hockett
authors.forename: J David
authors.initials: JD
authors.lastname: Robertson
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Gaffney
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Lanza
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Wickline
mesh_terms: D001161:Arteriosclerosis / Q000175:diagnosis* / Q000378:metabolism; D019921:Biotinylation; D002340:Carotid Artery Diseases / Q000175:diagnosis* / Q000378:metabolism; D003287:Contrast Media; D004655:Emulsions; D016894:Endarterectomy, Carotid; D005337:Fibrin / Q000378:metabolism*; D005461:Fluorine; D019786:Gadolinium DTPA; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D049329:Nanostructures; D010316:Particle Size; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D004655:Emulsions; D005461:Fluorine; D005337:Fibrin; D019786:Gadolinium DTPA