Vasogenic edema:
around SOL( tumors, abscesses,..)
- Involves only the white matter. Characteristically shows finger-like projections into the subcortical white matter in the gyri
Cytotoxic edema:
around acute infarction and hemorrhage
- Involves both gray and white matter
Periventricular edema:
around the ventricles
Absence of sulcal markings and poor differentiation of white and gray matter from diffuse bilateral cerebral hemispheric edema.
(a) Unenhanced CT imagedemonstrating vasogenic oedema
around a hyperdense brain metastasis . Note how the oedema extends through the white matter but spares the overlying grey matter cortex.
(b) Unenhanced CT demonstrating a wedge-shaped area of cytotoxic oedema
from an ischemic stroke involving the middle cerebral artery territory and both the grey matter cortex and the underlying white matter. Both are associated with mass effect causing distortion of the lateral ventricles.