Abstract:

Objective　To describe MR imaging features of normal fetal spine at different gestational ages.　Methods　Postmortem MR imaging was performed on 52 fetuses ranging from 15 to 40 gestational weeks. T2-weighted MR imaging of the lumbar spine was performed in the coronal, sagittal and axial planed. The following parameters were measured: signal and height of L1 disk, height and area of the L2 vertebral body and ossification center, area of vertebral canal, the ratio of ossification center to the overall size of the vertebral body, and the range of A-P vertebral body to vertebral canal.　Results　The L1 disk space increased linearly with gestational age (P<0.01). It appeared as a linear low-signal-intensity area in fetuses less than 21 weeks gestation but increasingly developed high signal intensity in the disk after 21weeks. The height and area of the vertebral body, ossification center, vertebral canal increased linearly with gestational age (P<0.01) .The ratio of ossification center to the overall size of the vertebral body increased with gestational age (P<0.01). The range of A-P vertebral body to vertebral canal was 1:1.3 to 1:0.6.　Conclusions　The normal growth and signal-intensity characteristics of the vertebral body, vertebral canal and spinal cord can be well described on Postmortem MR imaging.

Key words: Fetal specimen, Lumbar spine, Growth and development, Magnetic resonance imaging