title: [Gadolinium-loaded nanoparticle as a novel molecular imaging contrast agent for magnetic resonance imaging].
abstract: OBJECTIVE
  To synthesize a novel gadolinium-loaded nanoparticle as a molecular imaging contrast agent for magnetic resonance imaging.
  
  
  METHODS
  Gadolinium ion was incorporated within a silica nanoparticle. The size of this nanosized particle was determined by using transmission electron microscope. The spin-echo (SE) images of nine nanoparticle dilutions in vitro were obtained from a 1.5 T clinical scanner, compared with gadolinium diethylene triaminepenta acetate (Gd-DTPA). In vivo distribution of nanoparticle in Balb/c nude mice and Balb/c nude mice with nasopharyngeal carcinoma (NPC) xenografted CNE-2 tumors was studied at MR imaging, 30 sec, 5 min, 30 min, 1 h, 2 h, 4 h, and 24 h after intravenous administration.
  
  
  RESULTS
  The gadolinium-loaded nanoparticle was short rod-shaped, and approximately 30 to 40 nm in diameter. The value of longitudinal relaxativity (r(1)) of gadolinium nanoparticle was much higher than that of Gd-DTPA. Thirty minutes after injection the gadolinium nanoparticle, the signal intensities of liver, kidney and xenografted tumor increased from 226 +/- 10, 283 +/- 7 and 195 +/- 5 to 352 +/- 12, 328 +/- 10 and 245 +/- 7, respectively. The dynamic MRI scanning showed that gadolinium nanoparticles were mainly distributed in liver after intravenous administration. Strong enhancement was also detected in CNE-2 xenografted tumors.
  
  
  CONCLUSIONS
  A new gadolinium-loaded nanoparticle with high relaxativity was synthesized successfully, and might serve as a carrier for magnetic resonance molecular imaging.
authors.affiliation: State Key Laboratory of Oncology in Southern China, Imaging Diagnostic and Interventional Center, Cancer Center, Sun Yat-sen University, Guangzhou 510060, P R China.
authors.forename: Li-zhi
authors.initials: LZ
authors.lastname: Liu
authors.forename: Gang-jun
authors.initials: GJ
authors.lastname: Guo
authors.forename: Mu-sheng
authors.initials: MS
authors.lastname: Zeng
authors.forename: Yan-chun
authors.initials: YC
authors.lastname: Lü
authors.forename: Xue-wen
authors.initials: XW
authors.lastname: Liu
authors.forename: Chun-yan
authors.initials: CY
authors.lastname: Cui
authors.forename: Pei-hong
authors.initials: PH
authors.lastname: Wu
authors.forename: Li
authors.initials: L
authors.lastname: Li
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000737:chemistry / Q000493:pharmacokinetics*; D005260:Female; D019786:Gadolinium DTPA / Q000737:chemistry / Q000493:pharmacokinetics*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism / Q000473:pathology; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology; D010316:Particle Size; D014183:Transplantation, Heterologous
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA