, Volume 22, Issue 11, pp 2478-2486
Date: 30 May 2012

Evaluation of MR imaging with T1 and T2* mapping for the determination of hepatic iron overload

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Objectives

To evaluate MRI using T1 and T2* mapping sequences in patients with suspected hepatic iron overload (HIO).

Methods

Twenty-five consecutive patients with clinically suspected HIO were retrospectively studied. All underwent MRI and liver biopsy. For the quantification of liver T2* values we used a fat-saturated multi-echo gradient echo sequence with 12 echoes (TR = 200 ms, TE = 0.99 ms +  n × 1.41 ms, flip angle 20°). T1 values were obtained using a fast T1 mapping sequence based on an inversion recovery snapshot FLASH sequence. Parameter maps were analysed using regions of interest.

Results

ROC analysis calculated cut-off points at 10.07 ms and 15.47 ms for T2* in the determination of HIO with accuracy 88 %/88 %, sensitivity 84 %/89.5 % and specificity 100 %/83 %. MRI correctly classified 20 patients (80 %). All patients with HIO only had decreased T1 and T2* relaxation times. There was a significant difference in T1 between patients with HIO only and patients with HIO and steatohepatitis (P = 0.018).

Conclusions

MRI-based T2* relaxation diagnoses HIO very accurately, even at low iron concentrations. Important additional information may be obtained by the combination of T1 and T2* mapping. It is a rapid, non-invasive, accurate and reproducible technique for validating the evidence of even low hepatic iron concentrations.

Key Points

Hepatic iron overload causes fibrosis, cirrhosis and increases hepatocellular carcinoma risk.

MRI detects iron because of the field heterogeneity generated by haemosiderin.

T2* relaxation is very accurate in diagnosing hepatic iron overload.

Additional information may be obtained by T1 and T2* mapping.