Serial diffusion tensor imaging for early detection of radiation‐induced injuries to normal‐appearing white matter in high‐grade glioma patients

Purpose To study the potential of diffusion tensor imaging (DTI) to serve as a biomarker for radiation‐induced brain injury during chemo‐radiotherapy (RT) treatment. Materials and Methods Serial DTI data were collected from 18 high‐grade glioma (HGG) patients undergoing RT and 7 healthy controls. Changes across time in mean, standard deviation (SD), skewness, and kurtosis of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ a ), and transversal diffusivity (λ t ) within the normal‐appearing white matter (NAWM) were modeled using a linear mixed‐effects model to assess dose dependent changes of five dose bins (0–60 Gy), and global changes compared with a control group. Results Mean MD, λ a and λ t were all significantly increasing in >41 Gy dose regions (0.14%, 0.10%, and 0.18% per week) compared with <12 Gy regions. SD λ t had significant dose dependent time evolution of 0.019*dose per week. Mean and SD MD, λ a and λ t in the global NAWM of the patient group significantly increased (mean; 0.06%, 0.03%, 0.09%, and SD; 0.57%, 0.34%, 0.51 per week) compared with the control group. The changes were significant at week 6 of, or immediately after RT. Conclusion DTI is not sensitive to acute global NAWM changes during the treatment of HGG, but sensitive to early posttreatment changes. J. Magn. Reson. Imaging 2015;41:414–423. © 2013 Wiley Periodicals, Inc .