Brain Tumor Imaging: Posttherapy

This is the second and final volume of the American Journal of Neuroradiology Special Collection on Brain Tumor Imaging, which focuses on articles related to imaging of tumors after therapy. I would like to thank Mauricio Castillo, Editor-in-Chief of AJNR, for inviting me to be a Guest Editor and offering me this opportunity. During the past 12 months as the Guest Editor of this collection, I have learned a great deal while searching, cataloging, and reading through more than 100 articles on brain tumor imaging that were published in AJNR. Through this process, I came to realize the distinction between active tumor and treatment effect remains difficult, at times impossible, despite the progress made in imaging technology over the past few decades. Nonetheless, advances in imaging have made contributions to improving our understanding of injury to both tumor and normal brain following radiation therapy and chemotherapy and continue to push the limits of anatomic resolution to depict microscopic alteration. As therapy becomes more complex and sophisticated, the resultant dynamic changes in tumor biology and brain injury become challenging moving targets in the attempt by imaging methods to capture their underlying pathophysiology. The collection of articles in this volume echoes these challenges, but also identifies the roles of imaging in better depicting dynamic changes in tumor biology and reactive brain injury following therapy. No doubt much work needs to be done, but I am optimistic that we as a neuroimaging community have not lost an ounce of enthusiasm to tackle the perennial question of tumor versus treatment effect and to continue our search for the definitive imaging study that will solve this quandary.

I hope the readers of AJNR find the articles in this second volume useful.

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