Hepatic iron concentration: Noninvasive estimation by means of MR imaging techniques

PURPOSE: To identify a magnetic resonance (MR) imaging method sufficiently sensitive and specific in the estimation of hepatic iron content to obviate liver biopsy. MATERIALS AND METHODS: Thirty-eight patients underwent percutaneous needle biopsy of the liver with chemical measurement of the hepatic iron concentra tion and hepatic MR imaging with several spin-echo and gradient-recalled-ec ho (CRE) techniques. Correlations between MR imaging parameters and the hep atic iron concentration were determined. RESULTS: inverse curvilinear relationships were noted between several MR pa rameters and hepatic iron concentrations. CRE sequences with short repetiti on and echo times were more accurate and precise than spin-echo sequences f or the estimation of;hepatic iron concentration. A GRE sequence with a repe tition time of 18 msec, an echo time of 5 msec, and a flip angle of 10 degr ees 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%). CONCLUSION: MR imaging with these parameters is a rapid, noninvasive, and a ccurate modality for estimation of hepatic iron concentration; it is suffic iently accurate and precise to obviate liver biopsy for the purpose of meas uring hepatic iron concentration.