title: Contrast enhancement in experimental radiation-induced liver injury: comparison of hepatocellular and reticuloendothelial particulate contrast agents.
abstract: We compared the liver enhancement of two superparamagnetic agents, polycrystalline iron oxide nanoparticles (PION) and PION coated with asialofetuin (ASF), in an experimental model of focal radiation-induced hepatitis. PION, a reticuloendothelial system-directed agent, and PION-ASF, a hepatocellular-directed agent, were compared for time-dependent liver enhancement in an experimental model of radiation-induced liver injury. Using the reticuloendothelial system (RES)-directed PION, the normal, nonirradiated portion of the liver decreased in signal intensity (SI) with a mean negative enhancement of -66% +/- 4, whereas the irradiated portion (60 Gy, 3 days before imaging) of the liver decreased in SI by -24% +/- 2, significantly less (P <.05). SI changes in irradiated liver tissue using PION were dose-dependent, being more pronounced with lower radiation exposure. The difference in SI changes induced by PION-ASF between irradiated and nonirradiated liver was not statistically different, but SI decreased with a mean negative enhancement of -80% +/- 2. The RES-directed PION is more sensitive for the detection of radiation-induced hepatitis than is the hepatocyte-directed PION-ASF. The insensitivity of PION-ASF enhancement for diffuse liver injury may be clinically advantageous for detecting focal lesions in the presence of diffuse hepatic injury.
authors.affiliation: Contrast Media laboratory, Department of Radiology, University of California, San Francisco, CA 94143, USA.
authors.forename: M
authors.initials: M
authors.lastname: Stiskal
authors.forename: H C
authors.initials: HC
authors.lastname: Schwickert
authors.forename: F
authors.initials: F
authors.lastname: Demsar
authors.forename: T P
authors.initials: TP
authors.lastname: Roberts
authors.forename: D
authors.initials: D
authors.lastname: Szolar
authors.forename: R
authors.initials: R
authors.lastname: Weissleder
authors.forename: R C
authors.initials: RC
authors.lastname: Brasch
mesh_terms: D000818:Animals; D001212:Asialoglycoproteins; D003287:Contrast Media; D017352:Echo-Planar Imaging; D052203:Ferrosoferric Oxide; D060748:Fetuins; D006520:Hepatitis, Animal / Q000209:etiology / Q000473:pathology*; D007501:Iron; D007728:Kupffer Cells / Q000473:pathology; D008099:Liver / Q000473:pathology* / Q000528:radiation effects; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010087:Oxides; D011833:Radiation Injuries, Experimental / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D000509:alpha-Fetoproteins
chemical_list: D001212:Asialoglycoproteins; D003287:Contrast Media; D060748:Fetuins; D010087:Oxides; D000509:alpha-Fetoproteins; C017029:asialofetuin; D007501:Iron; D052203:Ferrosoferric Oxide