Purpose or Case Report: Magnetic Resonance Imaging is a powerful tool for the detection of ferromagnetic components. This property can be used for the early detection of pathologic conditions related to liver iron overload. Neonatal hemochromatosis and hemosiderosis are conditions associated with severe liver disease. Infections like parvovirus and cytomegalovirus, metabolic conditions and gestational allo-immune liver disease can produce neonatal hemochromatosis phenotype.
Fetal iron overload can be detected early by using T₂* multi-echo gradient sequence.
There are only few studies reporting standard T₂* values of the fetal liver at 1.5 T.
The aim of this study is to evaluated the standard T₂* values of the fetal liver using prenatal MRI with 3.0 T.
Methods & Materials: The T₂* sequence of the liver was obtained from eight fetuses (5 normal, 2 IUGR and one placenta hematoma) between 24 and 30 gestational weeks at 3.0 T Siemens Vero MRI system with a 6-channel flex coil and a 4-channel spine coil. T₂* weighted images were collected by multi-echo Spoiled Gradient Echo sequences with all the echoes flow compensated. The data were collected by four difference protocols. T₂ Half-Fourier Acquisition Single-shot Turbo Spin Echo (T2-HASTE) sequence was also performed as the reference. All the data analyses were performed by custom-written software in MATLAB^TM. T₂* map was created by a pixel wise exponential fitting, and only the voxels with a goodness of fit higher than 0.85 were considered as reliable results which were used in the calculation of average and standard deviation of T₂* value of the liver.
Results: Eight Singleton pregnant women underwent fetal MRI for research purposes in a 3.0 Tesla magnet. The average gestational age was 28.5 ± 3.8 weeks (range between 24 – 30 weeks).
The mean fetal liver T₂* value for the normal subjects were 15.8 ± 2.1 ms. The lowest value was 12.1 ms in a subject with 30 + 3/7 weeks of gestation, and the higher value was 21.6 ms in a subject with 30 + 5/7 weeks of gestation. No significant variation of T₂* values crossing gestational ages was found. The liver T₂* value in the case of placental hematoma at 25 weeks was 21.5 ms. The values for the IUGR subjects were 10 ms for the one at 35 weeks and 16.1 ms for the other one at 24 + 2/7 weeks.
Conclusions: Noninvasive evaluation of the fetal liver iron deposition is possible with T₂* MRI sequences using 3.0 Tesla. This study is important as a quantitative standard reference value especially in the assessment of chronic fetal liver conditions.