[Quantification of liver iron concentration using 1-Tesla MRI]

To evaluate the quantification of liver iron concentration using 1-Tesla magnetic resonance imaging (MRI) and its ability to diagnose or rule out hemochromatosis. To evaluate the role of 1.5-Tesla MRI in inconclusive cases.

Between 2002 and 2006, we used 1-Tesla MRI (Gandon method) and liver biopsy to quantify the liver iron concentration in 31 patients. Moreover, we used 1.5-Tesla MRI (according to Alústiza's model) and liver biopsy to determine the liver iron concentration in 10 additional patients and to check the results of 10 patients in whom 1-Tesla MRI detected iron overload.

In the first group of 31 patients, liver biopsy classified the liver iron concentration as normal (<36 micromol.Fe/g) in 11 patients, as hemosiderosis (36-80 micromol.Fe/g) in 15, and as hemochromatosis (>80 micromol.Fe/g) in 5. The correlation with the values calculated at MRI was 100% in the 5 cases with hemochromatosis; in the 15 patients with hemosiderosis, 5 were correctly classified and the liver iron concentration was overestimated in 10; of the 11 patients with normal liver iron concentration, 6 were correctly classified and 5 were overestimated. Quantification >80 at MRI has a sensitivity and negative predictive value of 100% and specificity of 50% for the diagnosis of hemochromatosis. Quantification <36 at MRI has a positive predictive value and specificity of 100% to identify the absence of iron overload. In the 10 patients with liver biopsy that underwent 1.5-Tesla MRI, there was a high correlation between the two techniques.

The reliability of the evaluation of liver iron concentration using 1-Tesla MRI is useful for ruling out hemochromatosis and identifying patients without iron overload. We observed a tendency to overestimate liver iron concentration in both patients with overload and in those without, and this limits the reliability of the technique. 1.5-Tesla MRI is a good alternative for quantifying liver iron concentration more precisely.