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  • Spleen...
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    Liver and iron. Organ distribution of iron.
    Yves Gandon - Medical Imaging, Rennes, France.

     
       Liver

    The increase of iron in the liver could be due:

    1. to a genetic hemochromatosis: the iron load is frequently significant with a ratio LIC/age>2. Right now, the diagnosis is done by genetic test and there is no place for MR. The level of overload could be estimated by hperferritinemia, if there is no other associated disease. In genetic hemochromatosis, the iron overload is due to a default of regulation of iron intestinal absorption and then the iron in excess is stored in the liver.
    2. to a dysmetabolic hemosiderosis, a frequent disease, combining a slight overheight, glucid or lipid metabolism dysregulation ... Patient are older. A splenic slight overload is frequent.
    3. to a chronic hemolysis, repeated blood transfusions (17, 18). In that context, splenic overload is predominant.
    4. to a cirrhosis (33) ...
    There is an other neonatal form of the disease. This is a severe genetic disease without any relation with the usual genetic hemochromatosis adult disease. MRI could help to make an antenatal diagnosis (34).

    The decrease of liver signal is usually homogeneous. Rarely the liver could be heterogeneous in case of cirrhosis, abnormalities of vascular distribution (35), hematoma after biopsy, underlying heterogeneous liver steatosis or presence of nodules (36).

    After 45 yo, the screening for a small hepatocellular carcinoma must be systematic, using 5 mm slice thickness and a T2 weighted sequence (breathhold T2* GRE sequence or respiratory gated T2 FSE.
     
    Multifocal HCC easily seen in a hypointense liver
    GRE "T1" 
    TR=120 ms, TE=4 ms, PA=90°
    GRE "T1" 
    TR=120 ms, TE=4 ms, PA=90°

     
     

       Spleen

    The splenic signal is usually unchanged in genetic hemochromatosis, except in some major overloads.

    On the other hand, a decrease of splenic signal is observed in secondary overload, when iron is predominantly stored in the reticuloendothelial system (37). 
     
    Decrease of the signal intensity of the spleen
    GRE "T2" 
    TR=120 ms, TE=14 ms, PA=20°

     
    Small siderotic nodules in the spleen are observed in case of portal hypertension.
     
     

       Pancreas

    Pancreatic signal intensity can decrease in some case of severe genetic hemochromatosis and is then usually associated with liver fibrosis or cirrhosis (38, 39). This pancreas iron overload is usually associated with a diabete.
     
    Decrease of the signal of the pancreas head
      (LIC=500µmol/g, Signa 1.5T)
    GRE "T2" 
    TR=120 ms, TE=14 ms, PA=20°

     
       Others

    A decrease of signal intensity of hypophysis (40), cardiac muscle (41), thyroid (42), lymph nodes (43) or even kidney (personal observation) could be observed. However there is no practical interest to detect them.
     
     

    Update: June 10th, 2001 Write to the webmaster