Cerebral radiation necrosis.

Cerebral radiation-induced injury ranges from acute reversible edema to late irreversible radiation necrosis (RN). Cerebral RN is poorly responsive to treatment, is associated with permanent neurological deficits and occasionally progresses to death. We review the literature regarding cerebral RN after radiotherapy for various brain and head and neck lesions and discuss its clinical features, imaging characteristics, pathophysiology and treatment. For new enhancing lesions on computed tomography or magnetic resonance imaging, apart from tumor progression or recurrence, RN needs to be considered in the differential diagnosis. Further studies are required to design chemoradiotherapy protocols that are effective in treating tumors while minimizing risk of RN. Current available treatments for RN, steroid and surgery, only relieve the mass effect. None of the experimental treatments to date have consistently been shown to reverse the pathologic process of RN.