PT  - JOURNAL ARTICLE
AU  - S Sinha
AU  - M E Bastin
AU  - J M Wardlaw
AU  - P A Armitage
AU  - I R Whittle
TI  - Effects of dexamethasone on peritumoural oedematous brain: a DT-MRI study
AID  - 10.1136/jnnp.2003.028647
DP  - 2004 Nov 01
TA  - Journal of Neurology, Neurosurgery & Psychiatry
PG  - 1632--1635
VI  - 75
IP  - 11
4099  - http://jnnp.bmj.com/content/75/11/1632.short
4100  - http://jnnp.bmj.com/content/75/11/1632.full
SO  - J Neurol Neurosurg Psychiatry2004 Nov 01; 75
AB  - Objectives: Glucocorticoids (dexamethasone) are thought to reduce peritumoural brain oedema by decreasing the permeability of neoplastic capillaries and/or enhancing the clearance of extracellular water. Diffusion tensor magnetic resonance imaging (DT-MRI) was used to measure the water diffusion parameters of oedematous and normal brain in a group of patients with intracranial tumours before and after steroid treatment. Methods: Fifteen patients with intracranial tumours (seven with high-grade glioma, four with metastatic carcinoma and four with meningioma) were examined before and 48–72 h after dexamethasone treatment (16 mg/day). The mean diffusivity (<D>) and fractional anisotropy (FA) were measured for oedematous brain and apparently normal contralateral white matter before and after steroid therapy. Results: In all three patient groups there was a significant decrease in <D> of oedematous brain after steroid treatment (p<0.01). There was no significant change in FA of oedematous brain after treatment in any of the three groups. There was also no significant change in either <D> or FA of apparently normal contralateral white matter after treatment. Conclusion: These data indicate that dexamethasone produces a localised reduction in the magnitude of extracellular water molecule mobility, and hence water content, in peritumoural oedematous brain. Furthermore, the magnitude of these changes is similar for both intra- and extra-axial tumours.