Magnetic Ressonance Image T2* for the Evaluation of Iron Overload in Patients with Hereditary Hemochromatosis. A New Guide for the Indication of Therapeutic Phlebotomies.

Hereditary hemochromatosis is highly prevalent in those with northern European ancestry (1 in 8 individuals are heterozygous and 1 in 100 – 200 are homozygous). It is characterized by laboratory tests as ferritin > 150 ng/mL, transferrine saturation > 40% and HFE mutations (C282Y and H63D). Presently the indications for treatment (therapeutic phlebotomies, TP) are based solely on the ferritin levels. It is possible that patients with moderate or even high levels of ferritin do not have iron overload. Performing liver biopsies would be an option for the actual evaluation, though invasive and risky. A non-invasive method to evaluate this deposition would be helpful in order to determine which patients actually demand TP.

To evaluate if the use of Magnetic Ressonance Image (MRI) is a method for measuring tissue iron and could be a new guide for the indication of therapeutic phlebotomies, nineteen patients (mean age 43,47 y.o, +/− 9,85, gender = 16 male, 3 female) with hereditary hemochromatosis were scanned with T2- star (T2*) (GE equipment, Milwaukee, USA). The median of ferritin level was 594 (21–9300) The MRI method was previously validated to chemical estimation of iron in thalassemic major patients undergoing liver biopsies. The evaluated organs were liver and heart.

All patients were in normal range of myocardial T2*. The images of four patients (25%), showed liver iron deposition. Eleven patients who presented serum ferritin levels below 600 ng/ml showed no liver iron deposition. Just one among five patients (20%), who presented ferritin levels between 601 and 1000 ng/ml showed hepatic iron overload. The three patients with ferritin levels higher than 1000 ng/ml had liver iron deposition quantified using liver T2* MRI techique.

MRI T2* showed that some patients who would have an indication for TP based on laboratory tests, might avoid these procedures based on image results of internal organs. These patients can have an image follow up in order to decide when would be the appropriate time to start TP. This method can also be used to evaluate the efficacy of TP in patients who have already received this treatment. A larger group of patients would have to be evaluated in order to validate these results.