A Systematic Review of the Literature on the Effects of Dexamethasone on the Brain From In Vivo Human-Based Studies: Implications for Physiological Brain Imaging of Patients With Intracranial Tumors

BACKGROUND: Among glucocorticoids, dexamethasone is most widely used for treatment of cerebral edema because of its long biological half-life and its low mineralocorticoid activity (sodium retaining). OBJECTIVE: A systematic review of the literature on the effects of dexamethasone on the brain from in vivo studies in humans. METHODS: A MEDLINE database search (via the PubMed interface) and an EMBASE database search (via the Dialog interface) of the past 35 years was performed. Every article relating to human use reported in English was included. In addition, references of all eligible articles were searched to identify other possible sources. RESULTS: Twenty-four articles matched the eligibility criteria. There were disparate methodologies and conflicting results, although they tended to indicate a decrease in blood-tumor barrier permeability, decreased tumoral perfusion, decreased tumoral diffusivity, and the possibility of decreased perfusion in contralateral normal-appearing brain tissue. CONCLUSION: Treatment with dexamethasone may alter imaging parameters from cerebral perfusion studies used in the management of brain tumors. In adequately powered studies, it may be possible to assess the longer term effects of dexamethasone on normal brain tissue to help optimize use with longer term survivors that are emerging as improvements in glioma treatment are made.