**5. Conclusions**

Radiation makes the noninvasive differentiation of abnormal-nontumor tissue vs tumor recurrence much more difficult. This is because radiation exhibits opposing behavior on key MRI modalities: specifically, on post-contrast T1, FLAIR, and GFA. Ultimately, combining multiple MRI metrics with clinical annotation allows the more successful differentiation of tumor recurrence from other post-treatment effects on MRI.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2077-0383/8/9/1287/s1, Figure S1: Comparing average signal intensities from Normal ROIs between treatment groups.

**Author Contributions:** Conceptualization, J.D.C., J.A.T., and D.R.O.; Data curation, J.D.C. and J.A.T.; Formal analysis, J.D.C.; Funding acquisition, J.D.C., J.A.T., and D.R.O.; Methodology, J.D.C., J.A.T., and D.R.O.; Project administration, J.D.C.; Resources, J.A.T. and D.R.O.; Software, J.D.C.; Supervision, J.A.T.; Visualization, J.D.C.; Writing—original draft, J.D.C., J.A.T., E.A., and D.R.O.; Writing—review & editing, J.D.C., J.A.T., E.A., and D.R.O.

**Funding:** This research was funded by the Cancer League of Colorado, grant number 183430-DO, and by the American Cancer Society, grant number IRG-16-184-56.

**Acknowledgments:** We would like to extend our thanks and appreciation to BK Kleinschmidt-DeMasters (B.K.D.) at the University of Colorado, Department of Pathology, for providing detailed histopathological examinations and Lisa Litzenberger for her assistance with the photomicrographs displayed in Figure 1.

**Conflicts of Interest:** The authors declare no conflicts of interest.
