脑部放疗后剂量依赖性白质损伤。

Dose-dependent white matter damage after brain radiotherapy.

作者信息

Connor Michael, Karunamuni Roshan, McDonald Carrie, White Nathan, Pettersson Niclas, Moiseenko Vitali, Seibert Tyler, Marshall Deborah, Cervino Laura, Bartsch Hauke, Kuperman Joshua, Murzin Vyacheslav, Krishnan Anitha, Farid Nikdokht, Dale Anders, Hattangadi-Gluth Jona

机构信息

Department of Radiation Medicine and Applied Sciences, University of California San Diego, United States.

Department of Radiation Medicine and Applied Sciences, University of California San Diego, United States; Multimodal Imaging Laboratory, University of California San Diego, United States.

出版信息

Radiother Oncol. 2016 Nov;121(2):209-216. doi: 10.1016/j.radonc.2016.10.003. Epub 2016 Oct 21.

DOI:10.1016/j.radonc.2016.10.003

PMID:27776747

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5136508/

Abstract

BACKGROUND AND PURPOSE

Brain radiotherapy is limited in part by damage to white matter, contributing to neurocognitive decline. We utilized diffusion tensor imaging (DTI) with multiple b-values (diffusion weightings) to model the dose-dependency and time course of radiation effects on white matter.

MATERIALS AND METHODS

Fifteen patients with high-grade gliomas treated with radiotherapy and chemotherapy underwent MRI with DTI prior to radiotherapy, and after months 1, 4-6, and 9-11. Diffusion tensors were calculated using three weightings (high, standard, and low b-values) and maps of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ), and radial diffusivity (λ) were generated. The region of interest was all white matter.

RESULTS

MD, λ, and λ increased significantly with time and dose, with corresponding decrease in FA. Greater changes were seen at lower b-values, except for FA. Time-dose interactions were highly significant at 4-6months and beyond (p<.001), and the difference in dose response between high and low b-values reached statistical significance at 9-11months for MD, λ, and λ (p<.001, p<.001, p=.005 respectively) as well as at 4-6months for λ (p=.04).

CONCLUSIONS

We detected dose-dependent changes across all doses, even <10Gy. Greater changes were observed at low b-values, suggesting prominent extracellular changes possibly due to vascular permeability and neuroinflammation.

摘要

背景与目的

脑放射治疗在一定程度上受到白质损伤的限制，这会导致神经认知功能下降。我们利用具有多个b值（扩散权重）的扩散张量成像（DTI）来模拟辐射对白质影响的剂量依赖性和时间进程。

材料与方法

15例接受放疗和化疗的高级别胶质瘤患者在放疗前、放疗后1个月、4 - 6个月以及9 - 11个月接受了MRI检查及DTI扫描。使用三种权重（高、标准和低b值）计算扩散张量，并生成各向异性分数（FA）、平均扩散率（MD）、轴向扩散率（λ）和径向扩散率（λ）的图谱。感兴趣区域为所有白质。

结果

MD、λ和λ随时间和剂量显著增加，同时FA相应降低。除FA外，在较低b值时观察到更大的变化。时间 - 剂量相互作用在4 - 6个月及之后具有高度显著性（p <.001），MD、λ和λ在9 - 11个月时高b值和低b值之间的剂量反应差异达到统计学显著性（分别为p <.001、p <.001、p =.005），λ在4 - 6个月时也达到统计学显著性（p =.04）。