title: Effect of superparamagnetic iron oxide on tumor-to-liver contrast at T2*-weighted gradient-echo MRI: comparison between 3.0T and 1.5T MR systems.
abstract: OBJECTIVE
  To compare 3.0T and 1.5T MR systems in terms of the effect of superparamagnetic iron oxide (SPIO) on tumor-to-liver contrast in T2*-weighted gradient-echo MRI.
  
  
  METHODS
  SPIO-enhanced gradient-echo MR images of the liver with four different TEs (3, 5.3, 6.5, and 8.5 msec) were obtained by means of 1.5T and 3.0T systems. Quantitative analyses of relative signal intensities (SIs) and relative tumor contrast and qualitative analyses of image quality and lesion conspicuity of the liver were performed in 22 patients, 16 of whom had malignant liver tumors.
  
  
  RESULTS
  With both 1.5T and 3.0T, at TE=8.4 msec, the relative SI of liver and relative tumor contrast were significantly (P<0.01) lower and higher, respectively, than that for any of the other TEs. There were no significant differences in the relative SI of the liver, relative tumor contrast, image quality, and tumor conspicuity for the same TE between the 1.5T and 3.0T systems.
  
  
  CONCLUSIONS
  Our results showed that the effect of SPIO on tumor-to-liver contrast at T2*-weighted gradient-echo imaging was similar for the 1.5T and 3.0T systems, and that the 8.4-msec TE was optimal of the four TEs used in this study at 3.0T.
authors.affiliation: Department of Radiology, Osaka University Graduate School of Medicine, Osaka, Japan. kim@radiol.med.osaka-u.ac.jp
authors.forename: Tonsok
authors.initials: T
authors.lastname: Kim
authors.forename: Takamichi
authors.initials: T
authors.lastname: Murakami
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hori
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Onishi
authors.forename: Kaname
authors.initials: K
authors.lastname: Tomoda
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000175:diagnosis / Q000473:pathology; D001653:Bile Ducts, Intrahepatic / Q000473:pathology; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000473:pathology; D018281:Cholangiocarcinoma / Q000175:diagnosis / Q000473:pathology; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000473:pathology; D003287:Contrast Media; D003911:Dextrans; D003937:Diagnosis, Differential; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007501:Iron; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide