Hepatic iron concentration: noninvasive estimation by means of MR imaging techniques.

Abstract

To identify a magnetic resonance (MR) imaging method sufficiently sensitive and specific in the estimation of hepatic iron content to obviate liver biopsy. Thirty-eight patients underwent percutaneous needle biopsy of the liver with chemical measurement of the hepatic iron concentration and hepatic MR imaging with several spin-echo and gradient-recalled-echo (GRE) techniques. Correlations between MR imaging parameters and the hepatic iron concentration were determined. Inverse curvilinear relationships were noted between several MR parameters and hepatic iron concentrations. GRE sequences with short repetition and echo times were more accurate and precise than spin-echo sequences for the estimation of hepatic iron concentration. A GRE sequence with a repetition time of 18 msec, an echo time of 5 msec, and a flip angle of 10 degrees showed close correlation between the hepatic iron concentration and the natural logarithm of the ratio of the signal intensity of liver to the SD of background noise (r = -0.94) and low coefficient of variation (12%). MR imaging with these parameters is a rapid, noninvasive, and accurate modality for estimation of hepatic iron concentration; it is sufficiently accurate and precise to obviate liver biopsy for the purpose of measuring hepatic iron concentration.