Evaluation of bone marrow iron by magnetic resonance imaging

Bone marrow iron was estimated by magnetic resonance imaging (MRI) using spin-echo sequences with multiple echoes in 22 patients with varying degrees of tissue storage iron. Levels of bone marrow iron concentration (BMIC) were determined chemically in biopsied specimens concurrently. Concentrations of serum iron, serum ferritin, and transferrin saturation were also measured to evaluate body iron status. Significant correlation was observed between BMIC and T2 relaxation rate (1/T2) (r=0.77;p<0.001) in all patients with BMIC levels below 400 μg/ml, while BMIC was not correlated with T2 in patients with extremely high BMIC levels. MRI was considered to be inappropriate for quantitation of 1/T2 in patients with extremely high BMIC due to an extreme shortening of T2 relaxation time. These observations suggest that MRI may be a useful and noninvasive method for systemic quantitative determination of bone marrow iron.