One year post third ventriculostomy. Moderate dilatation of the lateral and third ventricles and the upper portion of the cerebral aqueduct which tapers to focal stenosis in its inferior portion. The fourth ventricle is of normal calibre. This is in keeping with the known aqueduct stenosis. Thinning of the periventricular white matter and corpus callosum is consistent with the chronic nature of obstructive hydrocephalus.
Increased CSF flow in the pituitary fossa with flattening of the pituitary gland and a defect in the region of the tuber cinereum may relate to the third ventriculostomy. Linear CSF tract extending from right lateral ventricle through right frontal lobe is most likely the site of a previous ventricular drain.
Small focal area of CSF signal in the medial left thalamus with adjacent low MERGE signal that is low density on CT most likely represents an area of old haemorrhage with cystic encephalomalacia.