= EPENDYMITIS = PYOCEPHALUS
= inflammation of ependymal lining of one / more ventricles
Cause:
- rupture of periventricular abscess (thinner capsule wall medially)
- retrograde spread of infection from basal cisterns
CECT (necessary for diagnosis):
- thin uniform enhancement of involved ependymal lining
- often associated with intraventricular inflammatory exudate + septations
MR:
- intraventricular pus shows restricted diffusion on DWI
DDx: intraventricular blood (history!)
Cx: obstructive hydrocephalus ← occlusion at foramen of Monro / aqueduct
DDx: ependymal metastases, lymphoma, infiltrating glioma
= symmetric focal areas of hyperintensity on T2WI in normal individuals
Histo: patchy loss of ependyma with paucity of hydrophobic myelin (astrocytic gliosis), which allows migration of fluid out of the ventricle into interstitium
Location: anterior + lateral to frontal horns
- punctate / up to 1 cm in diameter
- grossly triangular in shape
= frequent complication of meningitis in infants (uncommon in adults)
Risk factors: craniotomy, diabetes (predisposes to staphylococcus and enterobacter infections)
- intraventricular debris ± restricted diffusion
- periventricular edema ± enhancement
- ventricular dilatation