SUPRATENTORIAL PARENCHYMA IN THE DEVELOPING FETAL BRAIN - IN-VITRO MRSTUDY WITH HISTOLOGIC COMPARISON

PURPOSE: To assess the in vitro MR signal of the developing brain thro ugh histologic comparisons, METHODS: Five healthy fetal specimens aged 16, 19, 22, 27, and 34 gestational weeks were studied in vitro using T1- and T2-weighted sequences in frontal and axial planes. Neuropathol ogic studies included sections in the same frontal plane. Comparison o f histologic sections with measurements of the relative widths of the layers of different signal intensities enabled us to assign cellular c orrespondence to each MR layer. RESULTS: In the cerebral mantle, a lay ered pattern was observed on both T1- and T2-weighted images. In the b asal ganglia, signal from the pallidum and thalamus was isointense wit h white matter from 16 to 22 weeks' gestation; then, from 27 and 34 we eks' gestation, the signal was relatively high on T1-weighted images a nd low on T2-weighted images. The neostriatum had a relatively low sig nal on T1-weighted images and a high signal on T2-weighted images from 16 to 27 weeks' gestation; then, at 34 weeks' gestation, the signal w as relatively high on T1-weighted images and low on T2-weighted images . CONCLUSION: MR imaging can clearly show specific patterns of growing fetal brain in vitro.