= RADIATION-INDUCED LEUKOENCEPHALOPATHY
= sequelae of radiotherapy combined with methotrexate therapy for leukemia
Incidence: in 25–30% after >9 months after treatment
Age: childhood
Cause: deposition of calcium within small vessels of previously irradiated brain parenchyma
- 85% without neurologic deficits
CT:
- thin reticular / serrated linear / punctate calcifications near corticomedullary junction, especially in basal ganglia + frontal and posterior parietal lobes
- symmetric low-attenuation process in white matter near corticomedullary area
MR:
- confluent diffuse periventricular distribution spreading peripherally with an irregular scalloped edge
= radiation-induced demyelination of periventricular white matter
Cause: whole-brain irradiation
- subclinical
Diffuse Necrotizing Leukoencephalopathy
Cause: intrathecal methotrexate ± whole brain irradiation
- rapidly deteriorating clinical course
- confluent pattern with scalloped margins in periventricular white matter extending out to subcortical U-fibers