Academic Radiology, University of Sheffield, Sheffield, UK.
Clinical Trials Research Unit, School of Health and Related Research, University of Sheffield, Sheffield, UK.
Biol Sex Differ. 2023 Mar 15;14(1):13. doi: 10.1186/s13293-023-00497-9.
The primary aim of the study is to test the null hypothesis that there are no statistically significant differences in intracranial volumes between male and female fetuses. Furthermore, we have studied the symmetry of the cerebral hemispheres in the cohort of low-risk fetuses.
200 normal fetuses between 18 and 37 gestational weeks (gw) were included in the cohort and all had in utero MR, consisting of routine and 3D-volume imaging. The surfaces of the cerebral ventricles, brain and internal table of the skull were outlined manually and volume measurements were obtained of ventricles (VV), brain parenchyma (BPV), extraaxial CSF spaces (EAV) and the total intracranial volume (TICV). The changes in those values were studied over the gestational range, along with potential gender differences and asymmetries of the cerebral hemispheres.
BPV and VV increased steadily from 18 to 37 gestational weeks, and as a result TICV also increased steadily over that period. TICV and BPV increased at a statistically significantly greater rate in male relative to female fetuses after 24gw. The greater VV in male fetuses was apparent earlier, but the rate of increase was similar for male and female fetuses. There was no difference between the genders in the left and right hemispherical volumes, and they remained symmetrical over the age range measured.
We have described the growth of the major intracranial compartments in fetuses between 18 and 37gw. We have shown a number of statistically different features between male and female fetuses, but we have not detected any asymmetry in volumes of the fetal cerebral hemispheres.
本研究的主要目的是检验男性和女性胎儿颅内体积无统计学差异的零假设。此外，我们还研究了低危胎儿队列中大脑半球的对称性。
本队列纳入了 200 例 18 至 37 孕周（gw）的正常胎儿，所有胎儿均接受了宫内磁共振检查，包括常规和 3D 容积成像。手动勾勒出侧脑室、脑实质和颅骨内板的表面，测量脑室（VV）、脑实质（BPV）、外腔隙 CSF 空间（EAV）和总颅内体积（TICV）。研究了这些值在整个妊娠期的变化，以及潜在的性别差异和大脑半球的不对称性。
BPV 和 VV 从 18 孕周增加到 37 孕周，因此 TICV 也在该期间稳定增加。在 24gw 后，男性胎儿的 TICV 和 BPV 增加速度明显快于女性胎儿。男性胎儿的 VV 更早出现，但男女胎儿的增加速度相似。左右半球体积在性别间无差异，且在测量的年龄范围内保持对称。
我们描述了 18 至 37gw 胎儿主要颅内腔室的生长情况。我们展示了男性和女性胎儿之间存在一些统计学上的差异特征，但未检测到胎儿大脑半球体积的任何不对称性。
