Background: Posterior fossa irradiation with or without whole brain irradiation results in high doses of radiation to the thalamus, hippocampus, and putamen, structures critical to cognitive functioning. As a result, children with brain tumors treated with cranial irradiation (CRT) may experience significant cognitive late effects. We sought to determine the effect of radiation to those structures on neuropsychological outcome.

Methods: Forty-seven children with a history of posterior fossa tumor (17 treated with surgery; 11 with surgery and chemotherapy; and 19 with surgery, chemotherapy, and CRT) underwent neuroimaging and neuropsychological assessment at a mean of 4.8 years after treatment, along with 17 healthy sibling controls. The putamen, thalamus, and hippocampus were segmented on each participant's magnetic resonance imaging for diffusion indices and volumes, and in the radiation treatment group, radiation dose to each structure was calculated.

Results: Performance on visuoconstruction and spatial learning and memory was lower in patient groups than controls. Volume of the thalamus, when controlling for age, was smaller in the patient group treated with CRT than other groups. Higher radiation doses to the putamen correlated with higher fractional anisotropy in that structure. Higher radiation dose to the hippocampus correlated with lower spatial learning, and higher dose to thalami and putamina to lower verbal and nonverbal reasoning.

Conclusions: All children with posterior fossa tumors, regardless of treatment modality, had cognitive deficits compared to their sibling controls. Posterior fossa irradiation may affect thalamic volume and aspects of verbal and nonverbal cognitive functioning.

Keywords: cognitive functioning; cranial irradiation; magnetic resonance imaging; posterior fossa tumor.

© 2024 The Author(s). Brain and Behavior published by Wiley Periodicals LLC.

背景： 后颅窝照射（包括或不包括全脑照射）会导致丘脑、海马和壳核等对认知功能至关重要的结构接受高剂量的辐射。因此，接受头颅放射治疗（CRT）的儿童可能会经历严重的认知晚期效应。我们旨在确定这些结构所受的辐射量如何影响神经心理学结果。

方法： 47名有后颅窝肿瘤病史的儿童（17人仅接受手术；11人接受手术和化疗；19人接受手术、化疗和CRT）在平均治疗后4.8年接受了神经影像学和神经心理学评估，同时还有17名健康兄弟姐妹作为对照。每个参与者的磁共振成像上对丘脑、壳核和海马进行分割以计算扩散指标和体积，在放射治疗组中还计算了每个结构的辐射剂量。

结果： 患者组在视觉构建能力和空间学习记忆方面的表现低于对照组。当控制年龄因素时，接受CRT治疗的患者的丘脑体积比其他组小。壳核所受的较高辐射剂量与该结构较高的分数各向异性相关。海马所受的较高辐射剂量与较低的空间学习能力相关，而丘脑和壳核所受的较高剂量则与较低的语言推理能力和非语言推理能力相关。

结论： 所有患有后颅窝肿瘤的儿童，无论治疗方式如何，都表现出认知功能障碍。后颅窝照射可能影响丘脑体积，并对言语和非言语的认知功能产生影响。

关键词： 认知功能；头颅放射治疗；磁共振成像；后颅窝肿瘤。