Whole Liver Iron Overload Measurement by Magnetic Iron Detector (MID). A Non Cryogenic Bio-Susceptometer.

Accurate assessment of body-iron accumulation is essential for diagnosis and therapy of iron-overload in diseases such as thalassemia, hereditary hemochromatosis and other forms of severe congenital or acquired anemias. At present, the gold standard to determine liver-iron concentration (LIC) is the invasive liver needle biopsy. This technique might lead to large error, in assessing iron burden, due to the heterogeneous distribution of iron deposition in the liver. SQUID bio-susceptometer and MRI are currently the only non-invasive validated methods for LIC measurements. The susceptometer presented herein, named Magnetic Iron Detector (MID), measures directly the iron overload in the whole liver. All of its components operate at room temperature. Since February 2005 about 150 patients and 90 healthy volunteers have been measured and the measures were obtained in blind. The local Ethics Committee approved the study and all subjects gave informed consent. The result of correlations with the LIC measurements by SQUID susceptometry (Dr. A. Piga, Turin) in 43 patients showed a R 0.86 (Fig 1). In 2 patients, affected by Congenital Hemocromatosis, we correlated the LIC measurement by MID with the assessment of the expected iron depletion obtained with the phlebotomy therapy R 0.94 (Fig 2). All the measurements were correlated with the serum-ferritin concentration values R 0.72. We obtained correlation with the LIC measurement by liver biopsy in 7 patients R 0.89, further measures are in progress. The reproducibility of the iron overload of the same patients, measured after a relatively short lapse of time, is better than 0.5g. In conclusion the data obtained shows that MID is a reliable instrument for the diagnosis of the liver iron overload and for the follow-up of the chelation therapy. It is simpler to operate being manageable directly in the Clinical Center and more affordable than competing techniques.

Fig. 1

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LIC measured by MID vs LIC measured by SQUID

Fig. 1

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LIC measured by MID vs LIC measured by SQUID

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Fig. 2

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The iron reduction of two hemochromatosis patients, under phebotomy therapy, compare with the reduction measured by the MID.

Fig. 2

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The iron reduction of two hemochromatosis patients, under phebotomy therapy, compare with the reduction measured by the MID.

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