Radiological features of hydrocephalus on CT brain (concise)
1) Ventricular dilatation (core feature)
- Enlargement of lateral ventricles (rounded frontal horns)
- Dilated 3rd ventricle
- ± Dilated 4th ventricle (helps localize obstruction)
- Temporal horns early dilatation (sensitive early sign)
2) Disproportionate ventriculomegaly
- Ventricles enlarged out of proportion to cortical sulci
- Helps differentiate from cerebral atrophy (where sulci also enlarged)
3) Periventricular lucency (transependymal CSF seepage)
- Hypodense rim around ventricles
- Indicates raised intraventricular pressure
4) Effacement of cortical sulci & cisterns
- Sulcal effacement (compressed brain parenchyma)
- Basal cisterns may be compressed
5) Ballooning of ventricular horns
- Frontal and occipital horns become rounded/bulbous
- Loss of normal concavity
6) Signs suggesting type (useful clinically)
- Obstructive (non-communicating):
- Dilatation proximal to block
- e.g., enlarged lateral + 3rd ventricle, normal 4th → aqueductal obstruction
- Communicating:
- All ventricles enlarged uniformly
7) Ancillary features
- Periventricular edema severity correlates with acuity
- Possible midline shift if asymmetric cause
- Identify cause: mass, hemorrhage, cyst, aqueduct stenosis
Ultra-short mnemonic
“VEPES”
- Ventricular dilatation
- Effaced sulci
- Periventricular lucency
- Early temporal horn enlargement
- Size disproportion (vs sulci)
