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Radiother Oncol. 2017 May;123(2):209-217. doi: 10.1016/j.radonc.2017.04.006. Epub 2017 May 2.

Regional susceptibility to dose-dependent white matter damage after brain radiotherapy.

Author information

1
Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California, United States.
2
Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California, United States; Center for Multimodal Imaging and Genetics, University of California San Diego, La Jolla, California, United States.
3
Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California, United States; Department of Psychiatry, University of California San Diego, La Jolla, California, United States; Center for Multimodal Imaging and Genetics, University of California San Diego, La Jolla, California, United States.
4
Department of Radiology, University of California San Diego, La Jolla, California, United States; Center for Multimodal Imaging and Genetics, University of California San Diego, La Jolla, California, United States.
5
Department of Radiology, University of California San Diego, La Jolla, California, United States; Department of Psychiatry, University of California San Diego, La Jolla, California, United States; Department of Neurosciences, University of California San Diego, La Jolla, California, United States; Center for Multimodal Imaging and Genetics, University of California San Diego, La Jolla, California, United States.
6
Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California, United States; Center for Multimodal Imaging and Genetics, University of California San Diego, La Jolla, California, United States. Electronic address: jhattangadi@ucsd.edu.

Abstract

BACKGROUND AND PURPOSE:

Regional differences in sensitivity to white matter damage after brain radiotherapy (RT) are not well-described. We characterized the spatial heterogeneity of dose-response across white matter tracts using diffusion tensor imaging (DTI).

MATERIALS AND METHODS:

Forty-nine patients with primary brain tumors underwent MRI with DTI before and 9-12months after partial-brain RT. Maps of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were generated. Atlas-based white matter tracts were identified. A secondary analysis using skeletonized tracts was also performed. Linear mixed-model analysis of the relationship between mean and max dose and percent change in DTI metrics was performed.

RESULTS:

Tracts with the strongest correlation of FA change with mean dose were the fornix (-0.46 percent/Gy), cingulum bundle (-0.44 percent/Gy), and body of corpus callosum (-0.23 percent/Gy), p<.001. These tracts also showed dose-sensitive changes in MD and RD. In the skeletonized analysis, the fornix and cingulum bundle remained highly dose-sensitive. Maximum and mean dose were similarly predictive of DTI change.

CONCLUSIONS:

The corpus callosum, cingulum bundle, and fornix show the most prominent dose-dependent changes following RT. Future studies examining correlation with cognitive functioning and potential avoidance of critical white matter regions are warranted.

KEYWORDS:

Diffusion tensor imaging; Dose-dependent; Radiation; Radiotherapy; White matter

PMID:
28460824
PMCID:
PMC5518466
DOI:
10.1016/j.radonc.2017.04.006
[Indexed for MEDLINE]
Free PMC Article

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