Magnetic-Susceptibility Measurement of Human Iron Stores

Abstract

We made direct noninvasive magnetic measurements of hepatic iron stores with a specially designed superconducting quantum-interference-device (SQUID) susceptometer in 20 normal subjects and in 110 patients with liver disease, iron deficiency, hereditary hemochromatosis, or transfusional iron overload. Magnetic in vivo measurements of liver non-heme iron were closely correlated with chemical in vitro measurements in liver-biopsy specimens (r = 0.98, P less than 10(-5) up to 115 mumol per gram of liver tissue (wet weight) or more. Magnetically determined storage-iron concentrations were below 6.0 mumol per gram in iron-deficient patients and normal men and premenopausal women, but they were raised (9.7 to 31.4 mumol) in 12 of 67 patients with liver disease and were greatly increased (22.9 to 117.7 mumol) in patients with untreated hereditary hemochromatosis or transfusional iron overload. Magnetic measurements of iron stores provide a new quantitative technique for early detection of hereditary hemochromatosis and for rapid evaluation of treatment regimens for transfusional iron overload.

Magnetite biomineralization in the human brain.

“…In past studies of iron storage and magnetic resonance imaging (MRI), it has been assumed universally that there are no permanently magnetized (ferromagnetic) materials present in human tissues (1,2). Similar assumptions have been made in virtually all biophysical assessments of human risk associated with exposure to static and extremely lowfrequency magnetic fields (3) and by critics (4) of epidemiological studies that suggest links between weak power-linefrequency magnetic fields and various human disorders (5,6).…”

Management of the Thalassemias

“…The best measure of the body iron load is the hepatic storage iron concentration, which reflects iron accumulations in both hepatocytes and reticuloendothelial macrophages (Kupffer cells). Therapy to maintain body iron at levels found in healthy, never-transfused individuals, corresponding to a hepatic iron of 0.2 -1.6 mg iron/g liver, dw (Brittenham et al 1982) may increase the probability of dose-related chelator toxicity. At the opposite extreme, body iron burdens corresponding to hepatic iron concentrations exceeding 15 -20 mg iron/g liver, dw place patients at risk of serious complications of iron loading (Brittenham et al 1994;Telfer et al 2000;Angelucci et al 2002;Jensen et al 2003).…”

“…Robust criteria to evaluate the effectiveness of iron-chelating therapy are derived from published results of prospective studies of patients with iron overload (Cartwright et al 1979;Brittenham et al 1982Brittenham et al , 1994Olivieri et al 1995) and are based on the ability of the chelator to reduce and maintain body iron at levels associated with favorable clinical outcomes. These criteria should be applied to the clinical evaluation of patients, including in clinical trials of new agents.…”

Iron overload and iron chelation therapy in patients with myelodysplastic syndrome treated by allogeneic stem‐cell transplantation: Report from the working conference on iron chelation of the Gruppo Italiano Trapianto di Midollo Osseo

“…Noninvasive techniques such as superconducting quantum interference device (SQUID) [42] and magnetic resonance imaging (MRI) [43] are now available for evaluation of liver iron. SQUID is available in only few centers in the world and has not been validated with respect to gold standard determination of LIC by liver biopsy.…”