Department of Psychology, the Neuroscience Institute, Georgia State University, United States of America.
Department of Psychology, the Neuroscience Institute, Georgia State University, United States of America; Department of Neurology, Emory University School of Medicine, United States of America; Atlanta VA Center of Excellence for Visual and Neurocognitive Rehabilitation, United States of America.
Neuroimage Clin. 2019;23:101894. doi: 10.1016/j.nicl.2019.101894. Epub 2019 Jun 10.
In posterior fossa tumor survivors, lower white matter integrity (WMI) in the right cerebellar-left frontal pathway has been well documented and appears to be related to proximity to the cerebellum, radiation treatment, as well as time since treatment in both cranial radiation and surgery-only treatment groups. The current study investigated theories of transneural degeneration following cerebellar tumor resection that may underlie or relate to reductions in WMI and regional brain volumes using correlations. We hypothesized a positive relationship between the volume of the right cerebellum and known white matter output pathways, as well as with the volume of structures that receive cerebellar projections along the pathway.
Adult survivors of childhood brain tumors were recruited (n = 29; age, M = 22 years, SD = 5; 45% female). Age- and gender-matched controls were also included (n = 29). Participants completed 3 T diffusion-weighted and T1 MPRAGE MRI scans. Brain structure volume relative to intracranial vault served as regional volumetric measures. Fractional anisotropy (FA) and radial diffusivity (RD) served as WMI measures. In the survivor group, partial correlations between WMI and regional volume included controlling for disease severity.
In posterior fossa tumor survivors, the volumes of the cerebellum, thalamus, and frontal lobe were correlated with WMI of the thalamic-frontal segment of the cerebellar-frontal pathway (r = 0.41-0.49, p < .05). Cerebellar atrophy was correlated with reduced WMI in the cerebellar-rubral segment (FA, r = -0.32 p > .05; RD, r = 0.53, p < .01). In the no-radiation survivor group, the regional volume of each structure along the pathway was associated with WMI in the cerebellar-rubral segment. In the radiation survivor group, significant correlations were found between the regional brain volume of each structure and the thalamic-frontal segment of the pathway.
The results of this multimodal neuroimaging study provide correlational evidence that the mechanism of injury subsequent to brain tumor treatment may be different depending on type of treatment(s). Without radiation, the primary mechanism of injury is cerebellar tumor growth, resection, and hydrocephalus. Therefore, the most proximal connection to that injury (cerebellar-rubral pathway) was correlated with reductions in volume along the pathway. In contrast, the survivor group treated with radiation may have had possible radiation-induced demyelination of the thalamic-frontal portion of the pathway, based on a strong correlation with volume loss in the cerebellum, red nucleus, thalamus, and frontal lobe.
在后颅窝肿瘤幸存者中，右侧小脑-左侧额叶通路的白质完整性（WMI）较低已得到充分证实，并且似乎与靠近小脑、放射治疗以及放射治疗和手术治疗组的治疗后时间有关。目前的研究使用相关性调查了小脑肿瘤切除术后可能导致或与 WMI 和区域脑体积减少有关的跨神经元变性理论。我们假设右侧小脑体积与已知的白质输出通路之间存在正相关，以及与沿通路接收小脑投射的结构的体积之间存在正相关。
招募了成年期儿童脑肿瘤幸存者（n=29；年龄，M=22 岁，SD=5；45%为女性）。还包括年龄和性别匹配的对照组（n=29）。参与者完成了 3T 扩散加权和 T1 MPRAGE MRI 扫描。相对于颅内穹窿的脑结构体积作为区域体积测量值。各向异性分数（FA）和径向扩散系数（RD）作为 WMI 测量值。在幸存者组中，在控制疾病严重程度的情况下，WM1 与区域体积之间的部分相关性。
在后颅窝肿瘤幸存者中，小脑、丘脑和额叶的体积与小脑-额叶通路的丘脑-额叶段的 WMI 相关（r=0.41-0.49，p<0.05）。小脑萎缩与小脑-红核段的 WMI 减少相关（FA，r=-0.32 p>0.05；RD，r=0.53，p<0.01）。在无放疗幸存者组中，沿通路的每个结构的区域体积与小脑-红核段的 WMI 相关。在放疗幸存者组中，发现每个结构的区域脑体积与通路的丘脑-额叶段之间存在显著相关性。
这项多模态神经影像学研究的结果提供了相关证据，表明脑肿瘤治疗后的损伤机制可能因治疗类型而异。没有放疗，主要的损伤机制是小脑肿瘤的生长、切除和脑积水。因此，与损伤最接近的连接（小脑-红核通路）与沿通路的体积减少相关。相比之下，接受放疗的幸存者组可能由于小脑、红核、丘脑和额叶的体积损失而导致放射诱导的丘脑-额叶部分脱髓鞘，这与 WMI 强烈相关。
