title: MR imaging with i.v. superparamagnetic iron oxide: efficacy in the detection of focal hepatic lesions.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy of superparmagnetic iron oxide (SPIO) in the detection of focal hepatic lesions on MR images.
  
  
  METHODS
  The study included 21 patients with 115 focal hepatic lesions and eight patients without focal hepatic lesions. T1- and T2-weighted MR images were obtained at 1.5 T before and 60 min after the end of injection of an SPIO agent. Contrast-enhanced CT scans were obtained in all patients within 10 days after MR imaging. The effect of SPIO on the signal intensity of the liver and spleen was assessed by using quantitative analysis of the region of interest. Efficacy was evaluated by using multiple criteria and unenhanced and SPIO-enhanced images. Evaluations included subjective assessment of image quality, counting the number of lesions detected, and statistical analysis of quantitative changes in the signal intensity of lesions and of normal liver.
  
  
  RESULTS
  By all criteria, SPIO-enhanced T2-weighted MR images were superior to unenhanced T2-weighted images and to contrast-enhanced CT scans. Conversely, by all criteria, SPIO-enhanced T1-weighted MR images were worse than unenhanced T1-weighted images and contrast-enhanced CT scans. The mean lesion-to-liver contrast on T2-weighted images was 317% on unenhanced images and 1745% on SPIO-enhanced images. For T1-weighted, the mean contrast was 26% on unenhanced images and 18% on SPIO-enhanced images.
  
  
  CONCLUSIONS
  SPIO is an efficacious contrast agent for the detection of focal hepatic lesions when T2-weighted MR images are used.
authors.affiliation: Department of Radiology, University of Washington Medical Center, Seattle 98195.
authors.forename: T C
authors.initials: TC
authors.lastname: Winter
authors.forename: P C
authors.initials: PC
authors.lastname: Freeny
authors.forename: H V
authors.initials: HV
authors.lastname: Nghiem
authors.forename: L A
authors.initials: LA
authors.lastname: Mack
authors.forename: R M
authors.initials: RM
authors.lastname: Patten
authors.forename: C R
authors.initials: CR
authors.lastname: Thomas
authors.forename: S
authors.initials: S
authors.lastname: Elliott
mesh_terms: D003287:Contrast Media / Q000009:adverse effects; D003911:Dextrans; D005069:Evaluation Studies as Topic; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron / Q000009:adverse effects; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides / Q000009:adverse effects; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide