[Visualization of radiation effects on the central nervous system]

Therapy-related side effects, which are detectable with magnetic resonance imaging (MRI) at high sensitivity, are one of the most frequent causes of morbidity in cancer patients. They can be observed in the treatment of central nervous system (CNS) diseases as well as in systemic therapy, including whole brain irradiation and chemotherapy and are more often seen due to the better overall survival. This review describes the most frequent acute and chronic therapy-related changes in the CNS and the imaging findings. Acute changes are often reversible while chronic changes can be observed up to several years after treatment.The differentiation of treatment-related from tumor-related changes might be very difficult, although modern imaging modalities such as MR spectroscopy or MR perfusion measurements supply helpful differential diagnostic information.