Estimation of Liver Iron Content with different MRI methods

Methods. 93 patients suspected for liver iron overload were examined by MRI to evaluate the amount of LIC. All examinations were performed at 1.5 T. Gradient echo (GRE) sequences were acquired according to the protocol published by Gandon et al [1] and the supplementary protocol for higher LIC by Rose et al. [2]. Furthermore, examinations with spin echo (SE) were performed with a protocol proposed by St. Pierre et al. [3]. For evaluation of GRE data, signal values are measured in manually drawn circular regions of interest (ROIs) in vessel-free parts of the liver and in the paraspinal muscles. Calculating the ratio of muscle reference value and liver signal, LIC can be estimated according to [1] and [2]. Spin echo data is analyzed using a more sophisticated method [ref. 3 and references cited there] based on calculation of T2 relaxation time. For each patient, LIC values were compared. The SE methods has an upper limit of 769 mmol/kg liver dry tissue, so patients with values of more than 750 μmol/g determined from SE data were excluded from analysis. Correlation between GRE vs. SE was determined for all values as well as separately for both GRE methods.