Clinical, Radiologic, and Pathologic Findings in Brain Radiation Injury

Stage (time to onset)SymptomsMRI/CTPETPathology
Acute (hours to weeks)Related to mass effect and ensuing increased ICP (headache, vomiting, altered consciousness)Edema; enhancing tumor massHypometabolismEdema; demyelinating plaques; gray–white junction fibrin exudate; hemorrhageic coagulation necrosis and vascular proliferation
Early delayed (weeks to 4 mo)Mixed 1 and 3White matter cyst formationHypometabolismMixed 1 and 3
Late delayed (4 mo to years)Focal neurologic deficits depending on the size and location of the lesionCortical atrophy Diffuse periventricular edema Expansile enhancing mass with focal hyperintensity on T2 and proton density imagesHypometabolismFibrinoid necrosis of the medium and small arteries with vascular proliferation; swollen gyri; hemorrhagic coagulation necrosis of the gray matter; white matter affected more than gray; axonal swelling, multifocal demyelination, hyalinization, and reactive gliosis
ChronicStable focal neurologic deficits as well as global effects causing personality changes and dementiaVascular dystrophic calcification with cystic changes; cortical atrophy; telangioectasiaHypometabolismReactive gliosis; subcortical cyst formation; vasculitis, arteritis, enhanced atherosclerosis, and vascular dystrophic calcification with cystic changes