Germinal matrix distribution.
A, Axial T2-weighted image from an infant of 23 weeks' gestation (PMA = 24 weeks). Germinal matrix can be seen in the posterior horns (arrowheads), anterior horns (short arrows), and at the caudothalamic notch (long arrows). Score: GM1, B1, C1, M1; TMS = 4.
B, Axial T2-weighted image from infant of 27 weeks' PMA (GA = 25 weeks). Germinal matrix can be seen in same distribution as in A, but is much less evident. Score: GM1, B1, M2, C2; TMS = 6.