Nuclear magnetic resonance study of iron overload in liver tissue.

Whole-tissue and homogenized samples of human liver were studied in a NMR spectrometer, T1 and T2 relaxation times were measured as a function of added inorganic or organic iron. When inorganic iron (Fe+3) was added, pronounced T1 and T2 shortening was noted. However, when organic iron, in the form of ferritin, was added, the amount of T1 and T2 relaxation enhancement was much reduced for the same amount of added iron. The in vitro ferritin results model the situation found in clinical studies of hemochromatosis. Only in cases of severe iron overload were significant decreases in relaxation times observed. The T2 relaxation time was the more reliable indicator of excessive levels of iron in the liver. The large range of T1 and T2 values encountered in normal volunteers precludes the use of MR to quantitatively measure iron levels in the liver. The T1 and T2 relaxation times measured at intervals for one individual tend to fluctuate as well, making the use of MR to follow the course of treatment of iron overload disorders unreliable.