摘要 目的 探讨围生期足月新生儿海马、海马旁回皮质形态及微结构变化，分析其发育规律。 方法 获取胎龄为37.6～44.4孕周正常足月新生儿颅脑T1加权像（T1WI）及多球壳弥散图像数据。识别并分别提取双侧海马、海马旁回皮质T1WI数据，测量其体积，并采用GBSS算法计算各向异性分数、平均弥散率、平均弥散峰度（MK）、轴突密度指数、方向分散指数等弥散参数值。 结果 足月新生儿双侧海马体积随孕龄增长而增大，双侧海马及海马旁回皮质MK值随孕龄增长而减小；双侧海马、海马旁回呈异质性发育；双侧海马旁回及周围白质同步发育。 结论 本研究描述了围生期足月新生儿双侧海马、海马旁回的正常发育特点，这些数据对评价足月新生儿脑发育及生后相关疾病提供了解剖学依据。 Abstract：Objective To investigate the changes in the morphology and microstructure of the cortex in the hippocampus and the parahippocampal gyrus in full-term neonates during the prenatal period, as well as related developmental rules. Methods Brain T1-weighted imaging (T1WI) and multiple-shell diffusion-weighted imaging (DWI) data were obtained from normal full-term neonates with a gestational age of 37.6-44.4 weeks. The T1WI data of the bilateral hippocampus and parahippocampal gyrus were identified and extracted, and their volume was measured. The GBSS algorithm was used to calculate related DWI parameters, including fractional anisotropy, mean diffusivity, mean kurtosis (MK), neurite density index, and orientation dispersion index. Results In the full-term neonates, the volume of the bilateral hippocampus increased with gestational age, while the MK values of the bilateral hippocampus and parahippocampal gyrus decreased with gestational age. Heterogeneous development of the bilateral hippocampus and parahippocampal gyrus was observed. A synchronous developmental pattern was observed in the bilateral parahippocampal gyrus and the surrounding white matter. Conclusion Normal developmental characteristics of the bilateral hippocampus and parahippocampal gyrus are described in this study, which provides an anatomical basis for evaluating brain development and related diseases in full-term neonates
