title: Nanoparticles as image enhancing agents for ultrasonography.
abstract: Nanoparticles have drawn great attention as targeted imaging and/or therapeutic agents. The small size of the nanoparticles allows them to target cells that are beyond capillary vasculature, such as cancer cells. We investigated the effect of solid nanoparticles for enhancing ultrasonic grey scale images in tissue phantoms and mouse livers in vivo. Silica nanospheres (100 nm) were dispersed in agarose at 1-2.5% mass concentration and imaged by a high-resolution ultrasound imaging system (transducer centre frequency: 30 MHz). Polystyrene particles of different sizes (500-3000 nm) and concentrations (0.13-0.75% mass) were similarly dispersed in agarose and imaged. Mice were injected intravenously with nanoparticle suspensions in saline. B-mode images of the livers were acquired at different time points after particle injection. An automated computer program was used to quantify the grey scale changes. Ultrasonic reflections were observed from nanoparticle suspensions in agarose gels. The image brightness, i.e., mean grey scale level, increased with particle size and concentration. The mean grey scale of mouse livers also increased following particle administration. These results indicated that it is feasible to use solid nanoparticles as contrast enhancing agents for ultrasonic imaging.
authors.affiliation: Biomedical Engineering Department, The Ohio State University, 270 Bevis Hall, 1080 Carmack Road, Columbus, OH 43210, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Levine
authors.forename: John S
authors.initials: JS
authors.lastname: Mattoon
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lee
authors.forename: Xueliang
authors.initials: X
authors.lastname: Pan
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Rosol
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry*; D005240:Feasibility Studies; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging*; D051379:Mice; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D012822:Silicon Dioxide