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

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.

SUBMITTER: Connor M 

PROVIDER: S-EPMC5518466 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature