MRI to assess iron stores – pro
The quantification and monitoring of tissue iron concentrations play important roles in the clinical management of patients with iron overload diseases such as thalassemia and hereditary hemochromatosis. Although blood tests such as serum ferritin and transferrin saturation are used for assessing the degree of iron overload in thalassaemia patients, these tests can be confounded by factors such as the presence of infection or tumours. In order to make a definitive measurement of the degree of iron overload, the currently accepted method is chemical analysis of iron from liver needle biopsy specimens. MRI promises to provide a non-invasive way of measuring hepatic iron.
There have been many studies, especially in the setting of hemochoromatosis that suggest that MRI can qualtify liver iorn stores reliably. In the non-invasive determination of the liver iron concentration several validated MRI methods are available. Most studies have confirmed that various methods of MEI based calcualtion of liver iron content compare well to biopsy or blood tests, but not all experts agree that the issue is setteld in all types of iron overload states. Some studies are continuing, for example: MRI Evaluation of Iron Overload in the Heart, Liver and Pancreas in Patients Receiving Multiple Blood Transfusions, NCT0062929 but many physicians feel that is sufficiently validated to be used clinically A recent Italian guideline (the Italians have the most experience with thalassemia and iron overload states) does recommend MRI for assessing iron stores. There is sufficient literature as well as the recent guideline to consider it to be no longer investigational.
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http://www.iascnapa.org/guidelines/Guidelines_IronOverload.pdf
Peter Nielsen Italian Society of Hematology guidelines for thalassemia and non-invasive iron measurements Haematologica. 2009 February; 94(2): 294–295
A. Olthof, P. Sijens, H. Kreeftenberg, P. Kappert, R. Irwan, E. van der Jagt, M. Oudkerk Correlation between serum ferritin levels and liver iron concentration determined by MR imaging: impact of hematologic disease and inflammation
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