正常胎儿脑沟超声观察及形态分析

目的观察正常胎儿大脑外侧裂(SF)、顶枕沟(POF)及距状沟(CF)等脑沟的形态发育特点,以及数据的测量,掌握胎儿脑沟回发育的特点。方法收集18~36周的单胎胎儿,记录SF、POF以及CF出现时间,形态特点,并测量SF高度,上缘宽度以及额叶颞叶间未覆盖的最小距离;POF和CF宽度、高度以及顶端角度。结果胎儿孕18周能探及SF,为平滑弧形,在19周后其上缘变平,21周SF几乎均变成梯形。此后,上缘长度随孕周缓慢增加;24周开始上缘两侧逐渐向脑实质内伸展,27周几乎所有胎儿均可见这一表现,此后上缘继续延伸,两脑叶间的未覆盖区逐渐缩小。POF在19~20周左右出现,最晚21周可被探及,在整个孕期宽度前期缓慢上升,后期缓慢下降,23周左右达到最宽,整个孕周高度逐渐增加,夹角逐渐变小。CF的出现较POF略晚,约在20~23周出现,最晚24周可被探及CF。其形态的变化过程与POF类似。结论SF 18周已出现,21周均由弧形转为梯形,25周左右成矩形,27周成“官帽”形。POF 21周最晚出现,26周左右时宽度与高度大致相等。CF最晚24周可被探及,在27~28周时宽度与高度大致相等。各大脑沟深度与孕周增加呈正相关,两脑叶间未覆盖区和顶枕沟角度与孕周增加呈负相关。

Objective To observe the morphological characteristics of brain grooves such as the lateral fetal cerebral fissure(Sylvain fissure SF),parieto-occipital fissure(POF),and calcarine fissure(CF)in normal fetus in order to master the characteristics of fetal sulcus gyrus development.Methods The single fetuses from 18 to 36 weeks were collected,the appearance time and morphological characteristics of SF,POF,and CF were recorded,and the height of SF,the width of the upper edge,the minimum uncovered distance between the frontal and temporal lobe,the width,height and top angle of POF and CF were measured.Results The fetus detected SF in pregnancy 18 weeks,but at this time it was a smooth arc.After 19 weeks,the shape of SF gradually changed,and its upper edge flattened.At 21 weeks,the fetus's SF almost becomes trapezoid.Thereafter,the length of the upper edge slowly increased with the gestational week;from the 24th week,both sides of the upper edge gradually extended into the brain parenchyma,and this phenomenon was almost visible to the ferns at 27 weeks.Thereafter,the upper edge continued to gradually extend,and the uncovered area between two brain lobes gradually shrinks.POF appeared around 19~20 weeks,and was detected at the latest 21 weeks.The width of the entire pregnancy period slowly rised in the early stage,and then decreases slowly in the later period,reached the widest around 23 weeks.The height gradually increased throughout the pregnancy week,and the angle gradually decreased.The appearance of CF was slightly later than that of POF.It occured about 20~23 weeks,and CF was detected at the latest 24 weeks.Its morphological change process was similar to that of POF.Conclusion SF appears at 18 weeks,turns from arc to trapezoid at 21 weeks,becomes rectangular at about 25 weeks,and become"official hat"at 27 weeks.POF appears the latest at 21 weeks,and its width and height are approximately equal at 26 weeks.CF can be detected at the latest 24 weeks,and its width and height are approximately equal at 27~28 weeks.The depth of each sulcus is positively correlated with the increase of gestational age,while the uncovered area between the two lobes and the angle of parietooccipital sulcus are negatively correlated with the increase of gestational age.