• In white matter adjacent to irradiated cerebral tumor
  • Adjacent brain tissue in field of head and neck tumor radiation therapy
  • Radiation causes cerebral small vessel alterations, wall thickening and direct glial and lesser extent neuronal injury
  • MRI
    • Ring-enhancing lesion, areas of hemorrhage, surrounded by edema
    • Difficult to distinguish from tumor recurrence
    • Increased diffusivity on DWI
    • Low cerebral blood volume
    • Low choline on spectroscopy
  • PET
    • Reduced metabolic avtivity
  • Tumors show decreased diffusivity, increased cerebral blood volume, high levels of choline, elevated metabolic activity
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Shah, Ritu, et al. “Radiation necrosis in the brain: imaging features and differentiation from tumor recurrence.” Radiographics 32.5 (2012): 1343-1359.

Yoon, Ra Gyoung, et al. “Differentiation of recurrent glioblastoma from delayed radiation necrosis by using voxel-based multiparametric analysis of MR imaging data.” Radiology 285.1 (2017): 206-213.

Barajas Jr, Ramon F., et al. “Differentiation of recurrent glioblastoma multiforme from radiation necrosis after external beam radiation therapy with dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging.” Radiology 253.2 (2009): 486-496.

Barajas, R. F., et al. “Distinguishing recurrent intra-axial metastatic tumor from radiation necrosis following gamma knife radiosurgery using dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging.” American journal of neuroradiology 30.2 (2009): 367-372.