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


CONCLUSIONS
• 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.
Department of Radiology, Innsbruck Medical University, Anichstraße 35, 6020, Innsbruck, Austria. benjamin.henninger@i-med.ac.at
B
B
Henninger
C
C
Kremser
S
S
Rauch
R
R
Eder
H
H
Zoller
A
A
Finkenstedt
H J
HJ
Michaely
M
M
Schocke
D000328:Adult; D000368:Aged; D001706:Biopsy; D005234:Fatty Liver / Q000175:diagnosis; D005260:Female; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019190:Iron Overload / Q000175:diagnosis*; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies
C103673:HFE protein, human; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I; D008565:Membrane Proteins