Background Congenital cytomegalovirus (CMV) infection exhibits polymicrogyria, intracranial calcification, white matter lesions, and several types of intracranial lesions on magnetic resonance imaging (MRI), in addition to various developmental disorders and epilepsies. However, little is known on the presence of hippocampal abnormality in this affliction. The aim of this study is to clarify the incidence of hippocampal abnormality in congenital CMV infection.

Methods Seventeen children diagnosed as having congenital CMV infection along with 17 age-matched pediatric controls were retrospectively evaluated by brain MRI and clinical review. The measurement data were obtained from conventional coronal sections in this retrospective study. Hippocampal malrotation (HIMAL) was defined as a hippocampal diameter ratio (i.e., the ratio of the height and width of the hippocampus) of >0.92.

Results Hippocampal diameter ratios were significantly higher in the congenital CMV infection group (0.99 [range: 0.70–1.58] on the right side and 0.85 [range: 0.66–1.39] on the left side) than in controls (0.71 [range: 0.58–0.91] and 0.70 [range: 0.50–1.00], respectively). HIMAL was present in 17 of 34 hippocampi (50%) in the congenital CMV infection group and 1 of 34 hippocampi (2.9%) in controls. No correlations were detected between HIMAL and intelligence quotient/developmental quotient or the occurrences of autism spectrum disorder or epilepsy.

Conclusion This study is the first to demonstrate the incidence of hippocampal abnormality to be significantly higher in congenital CMV infection patients than in age-matched controls. Further study is necessary to clarify the associations of HIMAL with other clinical and developmental features.

背景 先天性巨细胞病毒 (CMV) 感染除了各种发育障碍和癫痫外，在磁共振成像 (MRI) 上表现出多小脑回、颅内钙化、白质病变和几种类型的颅内病变。然而，关于这种疾病中海马异常的存在知之甚少。本研究的目的是阐明先天性巨细胞病毒感染中海马异常的发生率。

方法 对17名被诊断患有先天性巨细胞病毒感染的儿童和17名年龄匹配的儿童对照进行脑MRI和临床回顾性评估。在这项回顾性研究中，测量数据来自常规冠状切片。海马体旋转不良（HIMAL）定义为海马体直径比（即海马体高度和宽度的比值）>0.92。

结果 先天性 CMV 感染组的海马直径比（右侧为 0.99 [范围：0.70–1.58]，左侧为 0.85 [范围：0.66–1.39]）显着高于对照组（0.71 [范围：0.58– 0.91] 和 0.70 [范围：0.50–1.00]，分别）。先天性 CMV 感染组 34 个海马体中有 17 个（50%）存在 HIMAL，对照组 34 个海马体中有 1 个（2.9%）存在 HIMAL。HIMAL与智商/发育商或自闭症谱系障碍或癫痫的发生之间未检测到相关性。

结论 本研究首次证明先天性 CMV 感染患者的海马异常发生率显着高于年龄匹配的对照组。需要进一步研究以阐明 HIMAL 与其他临床和发育特征的关联。