Mapping Human Fetal Brain Maturation In Vivo Using Quantitative MRI

Presentation of conventionally acquired T2-weighted MR imaging contrasts (A, F, K, P) and quantitative MR imaging maps based on T1R (B, G, L, Q), T2R (C, H, M, R), R1 (D, I, N, S), and R2 (E, J, O, T). The color-coding, according to the T1-/T2-relaxation parameters, is indicated by the colored bars. The first (A, B, C, D, E) and the third columns (K, L, M, N, O) show MR imaging data from a fetus imaged at 32 + 4 weeks’ GA. The second (F, G, H, I, J) and the fourth columns (P, Q, R, S, T) show MR imaging data from a fetus imaged at 25 + 4 weeks’ GA. Brain myelination is indicated by a shortening of T1R/T2R (blue color-coding) and a prolongation of R1/R2 (yellow/orange color-coding). The color-coding of T1-relaxation parameters shows a distinct myelination of the medulla oblongata (L, N) and the midbrain tegmentum/tectum (B, D) at 32 + 4 weeks’ GA. At 25 + 4 weeks’ GA, only the medulla oblongata shows remarkable myelination (Q, S). The color-coding of T2-relaxation parameters indicates myelination of the medulla oblongata (M, O) at 32 + 4 weeks’ GA. Beginning T2R-shortening and R2-prolongation are visible in the medulla oblongata (R, T) at 25 + 4 weeks’ GA and in the midbrain tegmentum/tectum (C, E) at 32 + 4 weeks’ GA.

Pearson correlation between GA at MR imaging (x-axis) and the fetal brain maturity total score (y-axis) on the basis of SyMRI-generated (A and B) and conventionally acquired MR imaging data (C and D). Rater 1: A and C; rater 2: B and D.