High-field magnetic resonance imaging of the developing human brain from the 10th to the 16th week of gestational Age.

In the present work, high-field magnetic resonance imaging (HF-MRI) was applied to study the developing human brain paying particular attention to the structures of interest in pathology of malformation. The aim of the work was to evaluate the possible application of HF-MRI to the analysis of brain development in the absence of some limits of conventional histological technique. Seven formalin-fixed human fetuses of 50, 65, 70, 85, 110, 116 and 125 mm crown/ rump length (corresponding to a gestational age ranging from 10 to 16 weeks) were examined in an imager-spectrometer equipped with a 4. 7-tesla horizontal magnet with a 33-cm bore. In the brain of all the fetuses the telencephalic, mesencephalic and rhombencephalic vesicles were recognizable and an easy quantitative evaluation of the brain curvatures in the absence of distortion due to dissection was possible. Comparing fetuses at different gestational ages, the spatial modification of the different vesicles was evident. In fetuses at 16 weeks of gestational age, stratified compartments of the telencephalic wall were evident. The germinal zone and the cortical plate were visible: the germinal layer was identifiable as a hypointensity in the periventricular area. The subplate zone and the intermediate zone emitted a strong intensity signal. Our study demonstrates that HF-MRI can contribute to the study of the complex developmental events in the human brain from the 10th to 16th week of gestational age in a submillimetric scale of resolution. This technique can provide information about the morphology of the encephalic vesicles and their relations with the bone cavity that cannot be obtained with conventional methods and may be a useful adjunct to histological techniques.