Clinical presentation:
Adult male presents nocturia, thirst and headache.

This procedure is an air-encephalogram. It involves replacing cerebro-spinal fluid with air, during lumbar puncture under anaesthetic. This technique is yet another reason to be grateful for the invention of computed tomography.

The view shows a lateral skull with an enlarged pituitary fossa, thinning of anterior and posterior clinoid processes and poor definition of the floor of the fossa. Air has outlined a pedunculated soft tissue mass that fills the expanded pituitary fossa and elevates the third ventricle. The air outlines the thickened stalk of the lesion. The lateral ventricles and cerebral sulci are also shown.

The post-op. view demonstrates restoration of the margins of the pituitary fossa. The clivus and posterior clinoid process have become denser and better defined.