Radiation Necrosis MRI Index

Radiation necrosis is a delayed inflammatory response to radiation (typically 6–24 months post-treatment) that mimics tumor recurrence on standard contrast-enhanced MRI. Both appear as new or enlarging areas of contrast enhancement with surrounding edema. Accurate differentiation is critical: tumor recurrence requires more treatment (surgery/radiation), while necrosis requires steroids, bevacizumab, or observation.