Qualitative and Quantitative Magnetic Resonance Imaging in Haemoglobin H Disease: Screening for Iron Overload

Abstract OBJECTIVES: To evaluate the clinical utility of magnetic resonance imaging (MRI) in screening for iron overload in non-transfusion dependent Haemoglobin (Hb) H disease. PATIENTS AND METHODS: Thirty-six non-transfusion dependent HbH patients were evaluated with axial spin echo TI and gradient echo T2 MRI of the abdomen and heart. The ratios of signal intensities (SIR) of the liver, spleen, pancreas and heart to paraspinous muscles were calculated. SIR RESULTS: T2 SIR was more sensitive in detecting iron overload than TI SIR. Thirty-three livers, 13 spleens, six pancreas and one heart were diagnosed as having iron overload with T2 SIR, including three patients with normal serum ferritin. A positive diagnosis by T2 SIR was more closely related to that of qualitative grading than TI SIR. Serum ferritin was negatively correlated with hepatic SIR (T1 and T2), and with T2 SIR of the spleen and pancreas, even after adjustment for age. Liver haemosiderosis was confirmed in all six patients who underwent liver biopsies. Liver iron concentration of only one and a half times the normal was found in one patient with positive MR findings. CONCLUSION: MR is a non-invasive, effective method for early detection of iron overload particularly in the liver and spleen. Qualitative grading and quantitative T2 SIR data are equivalent in diagnosing iron overload. Routine screening of non-transfusion dependent HbH patients will identify high risk patients in whom early therapeutic intervention may prevent further complications and morbidity.