title: Sonochemically produced fluorocarbon microspheres: a new class of magnetic resonance imaging agent.
abstract: With the intent of increasing the signal-to-noise ratio (SNR) of fluorine magnetic resonance imaging and enabling new applications, we have developed a novel class of agents based on protein encapsulation of fluorocarbons. Microspheres formed by high-intensity ultrasound have a gaussian size distribution with an average diameter of 2.5 microns. As with conventional emulsions, these microspheres target the reticuloendothelial system. However, our sonochemically produced microspheres, because of a high encapsulation efficiency, show increases in the SNR of up to 300% compared to commercially available emulsions. We also demonstrate an increase in the circulation lifetime of the microspheres with the bloodstream by more than 30-fold with a chemical modification of the outer surface of the microsphere. Finally, by encapsulating mixtures of fluorocarbons that undergo solid/liquid phase transitions, we can map temperature in the reticuloendothelial system, with signal changes of approximately 20-fold over a 5 degrees C range.
authors.affiliation: Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Webb
authors.forename: M
authors.initials: M
authors.lastname: Wong
authors.forename: K J
authors.initials: KJ
authors.lastname: Kolbeck
authors.forename: R
authors.initials: R
authors.lastname: Magin
authors.forename: K S
authors.initials: KS
authors.lastname: Suslick
mesh_terms: D000818:Animals; D001831:Body Temperature; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003287:Contrast Media / Q000737:chemistry*; D004655:Emulsions; D005260:Female; D005466:Fluorocarbons / Q000097:blood / Q000737:chemistry*; D006207:Half-Life; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging; D008863:Microspheres; D012157:Mononuclear Phagocyte System / Q000033:anatomy & histology; D010316:Particle Size; D051381:Rats; D011916:Rats, Inbred F344; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013499:Surface Properties; D014018:Tissue Distribution; D014465:Ultrasonics
chemical_list: D003287:Contrast Media; D004655:Emulsions; D005466:Fluorocarbons; D012710:Serum Albumin, Bovine