title: In vivo tissue characterization using magnetic techniques.
abstract: Among the few non-invasive methods to quantify liver iron deposits, magnetic resonance imaging (MRI) and biomagnetic liver susceptometry (BLS) have been considered the best to evaluate iron overload in the body. This diagnosis is necessary for patients who regularly receive red blood cells transfusion and that have a genetic disorder known as hemochromatosis. In this work, we present the evaluation of the clinical usefulness of MRI and BLS of hepatic tissue to quantify iron deposits in non-transfused and transfused patients. Liver iron evaluation by MRI and BLS were performed in a group of 48 patients. The MRI images weighted in T2 were acquired using multi-slice single-spin-echo (SSE) and single-slice multi-spin-echo (MSE), conducted on a 1.5 T whole body scanner. BLS measurements were performed using an ac superconducting susceptometer based on SQUID. Typically MRI is able to evaluate iron overload in liver as high as 30 mg/g(dry tissue) when using MRI scanners provided with specially designed pulse sequences. For higher iron concentrations susceptibility measurement works better than MRI to evaluate higher iron overloads in the liver, because in this case there is saturation of MRI signal.
authors: Departamento de Física e Matemática, FFCLRP, Universidade de São Paulo, Ribeirão Preto, SP, Brazil. adilton@biomag.usp.br
authors: A A
authors: AA
authors: Carneiro
authors: G R
authors: GR
authors: Vilela
authors: J B
authors: JB
authors: Fernandes
authors: D
authors: D
authors: Araújo
authors: O
authors: O
authors: Baffa
authors: J
authors: J
authors: Elias
authors: G
authors: G
authors: St Pierre
authors: I L
authors: IL
authors: Angulo
authors: D T
authors: DT
authors: Covas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D004574:Electromagnetic Fields; D005260:Female; D006801:Humans; D019190:Iron Overload / Q000175:diagnosis / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008280:Magnetics / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D014018:Tissue Distribution / Q000502:physiology