Karunamuni Roshan, Bartsch Hauke, White Nathan S, Moiseenko Vitali, Carmona Ruben, Marshall Deborah C, Seibert Tyler M, McDonald Carrie R, Farid Nikdokht, Krishnan Anithapriya, Kuperman Joshua, Mell Loren, Brewer James B, Dale Anders M, Hattangadi-Gluth Jona A
Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California.
Department of Radiology, University of California San Diego, La Jolla, California.
Int J Radiat Oncol Biol Phys. 2016 Feb 1;94(2):297-304. doi: 10.1016/j.ijrobp.2015.10.026. Epub 2015 Oct 21.
Radiation-induced cognitive deficits may be mediated by tissue damage to cortical regions. Volumetric changes in cortex can be reliably measured using high-resolution magnetic resonance imaging (MRI). We used these methods to study the association between radiation therapy (RT) dose and change in cortical thickness in high-grade glioma (HGG) patients.
We performed a voxel-wise analysis of MRI from 15 HGG patients who underwent fractionated partial brain RT. Three-dimensional MRI was acquired pre- and 1 year post RT. Cortex was parceled with well-validated segmentation software. Surgical cavities were censored. Each cortical voxel was assigned a change in cortical thickness between time points, RT dose value, and neuroanatomic label by lobe. Effects of dose, neuroanatomic location, age, and chemotherapy on cortical thickness were tested using linear mixed effects (LME) modeling.
Cortical atrophy was seen after 1 year post RT with greater effects at higher doses. Estimates from LME modeling showed that cortical thickness decreased by -0.0033 mm (P<.001) for every 1-Gy increase in RT dose. Temporal and limbic cortex exhibited the largest changes in cortical thickness per Gy compared to that in other regions (P<.001). Age and chemotherapy were not significantly associated with change in cortical thickness.
We found dose-dependent thinning of the cerebral cortex, with varying neuroanatomical regional sensitivity, 1 year after fractionated partial brain RT. The magnitude of thinning parallels 1-year atrophy rates seen in neurodegenerative diseases and may contribute to cognitive decline following high-dose RT.
辐射诱发的认知缺陷可能是由皮质区域的组织损伤介导的。使用高分辨率磁共振成像（MRI）可以可靠地测量皮质的体积变化。我们采用这些方法研究了高级别胶质瘤（HGG）患者的放射治疗（RT）剂量与皮质厚度变化之间的关联。
我们对15例接受分次部分脑RT的HGG患者的MRI进行了体素分析。在RT前和RT后1年采集三维MRI。使用经过充分验证的分割软件对皮质进行划分。手术腔不予考虑。每个皮质体素被赋予两个时间点之间的皮质厚度变化、RT剂量值以及按脑叶划分的神经解剖学标签。使用线性混合效应（LME）模型测试剂量、神经解剖位置、年龄和化疗对皮质厚度的影响。
RT后1年可见皮质萎缩，高剂量时影响更大。LME模型的估计显示，RT剂量每增加1 Gy，皮质厚度降低-0.0033 mm（P<0.001）。与其他区域相比，颞叶和边缘皮质每Gy的皮质厚度变化最大（P<0.001）。年龄和化疗与皮质厚度变化无显著关联。
我们发现，在分次部分脑RT后1年，大脑皮质出现剂量依赖性变薄，不同神经解剖区域的敏感性不同。变薄的程度与神经退行性疾病中观察到的1年萎缩率相似，可能导致高剂量RT后的认知衰退。
