Differentiation of Tumor Recurrence from radiation-induced Necrosis Using Diffusion Tensor Imaging

Introduction: Surgical resection and chemotherapy alone have proven to be insufficient in treatment of patients with primary and metastatic brain tumors. As a result, the various forms of radiotherapy, such as external-beam radiation, radiosurgery have become important therapeutic adjuncts. The appearance of a new enhancing lesion after radiation treatment may represent tumor recurrence, radiation-induced demyelination, or radiation necrosis of the brain. Differentiation among these possibilities can be difficult with conventional MR imaging. Diffusion-weighted imaging (DWI) has been reported to be helpful in distinguishing tumor recurrence and radiation damage (1). Our study was designed to explore the ability of DTI in assessing new contrast enhancing lesions as tumor recurrence or non-neoplastic therapy related change.