From the Croatian Institute for Brain Research (V.K., A.Š., M.V.), School of Medicine, University of Zagreb, Zagreb, Croatia.
Department of Biomedical Imaging and Image-Guided Therapy (G.K., E.S., M.W., D.P.)
AJNR Am J Neuroradiol. 2019 Mar;40(3):576-581. doi: 10.3174/ajnr.A5986. Epub 2019 Feb 21.
In subjects with agenesis of the corpus callosum, a variety of structural brain alterations is already present during prenatal life. Quantification of these alterations in fetuses with associated brain or body malformations (corpus callosum agenesis and other related anomalies) and so-called isolated cases may help to optimize the challenging prognostic prenatal assessment of fetuses with corpus callosum agenesis. This fetal MR imaging study aimed to identify differences in the size of the prenatal hippocampus between subjects with isolated corpus callosum agenesis, corpus callosum agenesis and other related anomalies, and healthy controls.
Eighty-five in utero fetal brain MR imaging scans, (20-35 gestational weeks) were postprocessed using a high-resolution algorithm. On the basis of multiplanar T2-TSE sequences, 3D isovoxel datasets were generated, and both hippocampi and the intracranial volume were segmented.
Hippocampal volumes increased linearly with gestational weeks in all 3 groups. One-way ANOVA demonstrated differences in hippocampal volumes between control and pathologic groups (isolated corpus callosum agenesis: left, = .02; right, = .04; corpus callosum agenesis and other related anomalies: < .001). Differences among the pathologic groups were also present for both sides. Intracranial volume and right and left hippocampal volume ratios were different between corpus callosum agenesis cases and controls ( < .001). When we corrected for intracranial volume, no differences were found between corpus callosum agenesis and other associated anomalies and isolated corpus callosum agenesis (left, = .77; right, = .84). Hippocampal size differences were more pronounced at a later gestational age.
Callosal agenesis apparently interferes with the normal process of hippocampal formation and growth, resulting in underdevelopment, which could account for certain learning and memory deficits in individuals with agenesis of the corpus callosum in later life.
在胼胝体发育不全的患者中，在产前就已经存在多种结构脑改变。对合并脑或身体畸形（胼胝体发育不全和其他相关异常）和所谓孤立病例的胎儿进行这些改变的定量分析，可能有助于优化胼胝体发育不全胎儿具有挑战性的产前预后评估。本项胎儿磁共振成像研究旨在比较孤立性胼胝体发育不全、胼胝体发育不全合并其他相关异常和健康对照组胎儿的产前海马体积大小差异。
对 85 例宫内胎儿脑磁共振成像扫描（20-35 孕周）进行后处理，使用高分辨率算法。在多平面 T2-TSE 序列的基础上，生成三维等体数据集，并对海马和颅内容积进行分割。
在所有 3 组中，海马体积均随孕周呈线性增长。单因素方差分析显示对照组和病变组的海马体积存在差异（孤立性胼胝体发育不全：左侧， <.02；右侧， <.04；胼胝体发育不全和其他相关异常： <.001）。病变组之间也存在双侧差异。胼胝体发育不全组的颅内容积和右侧及左侧海马容积比与对照组不同（ <.001）。当我们校正颅内容积后，胼胝体发育不全和其他相关异常与孤立性胼胝体发育不全之间没有差异（左侧， <.77；右侧， <.84）。在较大的孕周时，海马大小的差异更为明显。
胼胝体缺如显然干扰了海马形成和生长的正常过程，导致发育不全，这可能解释了胼胝体发育不全患者在以后生活中出现的某些学习和记忆缺陷。
