Purpose. To evaluate the possibility of structural analysis of the fetal brain using the method of diffusion-tensor magnetic resonance imaging (DTI). Materials and methods. Imaging of 20 fetal brains at 20-39 gestational weeks were acquired on 3.0T MRI scanner GE Discovery MR750W. The study population included 20 pregnant women that gave written, informed consent for using their clinical data for research purposes prior to the examination. The study population was consisted of fetuses for which fetal MRI was clinically indicated according to gynecological anamnesis and the results of ultrasound screening. Pregnant women were examined in the supine position (feet first), and no contrast agents or sedatives were used. Methodology included obtaining T2 SSFSE (TE=70-90 ms) in 3 orthogonal planes to evaluate anatomic structures and planning the region of interest; T1 (TR=204, TE=4,7), DWI (TR=4000, TE=70; b=700), slice thickness 3-4 mm. Then twice applied DTI: TR/TE: 2200/63 ms, b-factor 700 s/mm2. The duration of the MR-MP was from 1 min. 31 sec. to 3 min. 47sec. The region of interest included corticospinal tracts (CST), the genu and the splenium of the corpus callosum (GCC and SCC), white matter in both hemispheres of the brain. DTI calculation and postprocessing were performed after transferring diffusion-weighted images to an off-line workstation and was obtained in each case manually. Results. In all cases magnetic resonance tomograms of the fetal brain were obtained, the value of the fractional anisotropy coefficient (CFA) was measured, 3D-tractograms were constructed. The earliest detection of the conducting pathways of the brain was determined at the 20 week of gestation. It wasn't possible to measure CFA in all cases: the visualization frequency of the tracts in the projection of GCC was 87.5%, SCC-68.7%, right CST-75.0%, left CST-75.0%, white matter in both hemispheres of the brain-92.5%. A significant increase of CFA was observed at 35-36 weeks of pregnancy. With the increasing of the gestational period, a clearer visual differentiation of the number and volume of tracts passing in each direction was detected. Conclusion. DTI provides a unique possibility of in vivo utero study of the brain's microstructure and myelinization. We have studied the dynamics of the CFA of 20 fetal brains. The increase of CFA to 35-36 gestational weeks might correspond to myelinization maturity of the fetal brain. DTI of the fetal brain is a viable, safe and noninvasive method that is promising in evaluating myelinization of white matter and revealing pathological changes prior to visualization of gross structural abnormalities determined by ultrasound or conventional MRI. DTI can potentially act as a marker for the integrity and development of the conductive pathways, differentiate between full-term and premature infants.
|Журнал||Russian Electronic Journal of Radiology|
|Состояние||Опубликовано - 1 янв 2018|
Предметные области Scopus
- Радиология, радиационная медицина и радионуклидная визуализация