title: Liver iron concentration evaluated by two magnetic methods: magnetic resonance imaging and magnetic susceptometry.
abstract: Quantification of liver iron concentration (LIC) is crucial in the management of patients suffering from certain pathologies that can produce iron overload, such as Cooley's anemia and hemochromatosis. All of these patients must control the level of iron deposits in their organs to avoid the toxicity of high LIC, which is potentially lethal. This paper describes experimental protocols for LIC measurement using two magnetic techniques: magnetic resonance imaging (MRI) and biomagnetic liver susceptometry (BLS). MRI proton transverse relaxation rate (R2) and image intensity, evaluated pixel by pixel, were used as indicators of iron load in the tissue. LIC measurement by BLS was performed using an AC superconducting susceptometer system. A group of 23 patients with a large range of iron overload (0.9 to 34.5 mgFe/g(dry tissue)) was evaluated with both techniques (MRI x BLS). A significant linear correlation (r = 0.89-0.95) was found between the LIC by MRI and by BLS. These results show the feasibility of using two noninvasive methodologies to evaluate liver iron store in a large concentration range. Both methodologies represent an equivalent precision.
authors.affiliation: Departamento de Física e Matemática, FFCLRP, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil. adilton@biomag.usp.br
authors.forename: Antonio Adilton O
authors.initials: AA
authors.lastname: Carneiro
authors.forename: Juliana P
authors.initials: JP
authors.lastname: Fernandes
authors.forename: Draulio B
authors.initials: DB
authors.lastname: de Araujo
authors.forename: Jorge
authors.initials: J
authors.lastname: Elias
authors.forename: Ana L C
authors.initials: AL
authors.lastname: Martinelli
authors.forename: Dimas T
authors.initials: DT
authors.lastname: Covas
authors.forename: Marco A
authors.initials: MA
authors.lastname: Zago
authors.forename: Ivan L
authors.initials: IL
authors.lastname: Angulo
authors.forename: Timothy G
authors.initials: TG
authors.lastname: St Pierre
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Baffa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D015415:Biomarkers / Q000378:metabolism; D002648:Child; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007501:Iron / Q000378:metabolism*; D019189:Iron Metabolism Disorders / Q000175:diagnosis* / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D007501:Iron