title: MR characterization of hepatic storage iron in transfusional iron overload.
abstract: OBJECTIVE
  To quantify the two principal forms of hepatic storage iron, diffuse, soluble iron (primarily ferritin), and aggregated, insoluble iron (primarily hemosiderin) using a new MRI method in patients with transfusional iron overload.
  
  
  METHODS
  Six healthy volunteers and 20 patients with transfusion-dependent thalassemia syndromes and iron overload were examined. Ferritin- and hemosiderin-like iron were determined based on the measurement of two distinct relaxation parameters: the "reduced" transverse relaxation rate, RR2 , and the "aggregation index," A, using three sets of Carr-Purcell-Meiboom-Gill (CPMG) datasets with different interecho spacings. Agarose phantoms, simulating the relaxation and susceptibility properties of tissue with different concentrations of dispersed (ferritin-like) and aggregated (hemosiderin-like) iron, were used for validation.
  
  
  RESULTS
  Both phantom and in vivo human data confirmed that transverse relaxation components associated with the dispersed and aggregated iron could be separated using the two-parameter (RR2 , A) method. The MRI-determined total hepatic storage iron was highly correlated (r = 0.95) with measurements derived from biopsy or biosusceptometry. As total hepatic storage iron increased, the proportion stored as aggregated iron became greater.
  
  
  CONCLUSIONS
  This method provides a new means for noninvasive MRI determination of the partition of hepatic storage iron between ferritin and hemosiderin in iron overload disorders.
authors.affiliation: Imaging, Discovery Medicine & Clinical Pharmacology, Bristol Myers Squibb, Princeton, New Jersey, USA.
authors.forename: Haiying
authors.initials: H
authors.lastname: Tang
authors.forename: Jens H
authors.initials: JH
authors.lastname: Jensen
authors.forename: Christina L
authors.initials: CL
authors.lastname: Sammet
authors.forename: Sujit
authors.initials: S
authors.lastname: Sheth
authors.forename: Srirama V
authors.initials: SV
authors.lastname: Swaminathan
authors.forename: Kristi
authors.initials: K
authors.lastname: Hultman
authors.forename: Daniel
authors.initials: D
authors.lastname: Kim
authors.forename: Ed X
authors.initials: EX
authors.lastname: Wu
authors.forename: Truman R
authors.initials: TR
authors.lastname: Brown
authors.forename: Gary M
authors.initials: GM
authors.lastname: Brittenham
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007501:Iron / Q000378:metabolism / Q000493:pharmacokinetics; D019190:Iron Overload / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008107:Liver Diseases / Q000175:diagnosis* / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013789:Thalassemia / Q000378:metabolism* / Q000628:therapy; D014018:Tissue Distribution; D065227:Transfusion Reaction
chemical_list: D007501:Iron
keywords: MRI; ferritin, hemosiderin, iron quantification; hepatic storage iron; iron overload