Factors influencing the development of periventricular lucencies in patients with raised intracranial pressure.

Sixty patients with raised intracranial pressure and lowered attenuation areas around the lateral ventricles ('periventricular lucency', PVL) on CT scanning were reviewed, and compared with a control group of 90 similar patients who did not have PVL. It was confirmed that PVL tends to occur in patients with acute or subacute obstructive hydrocephalus due to a tumour, and is more common in the presence of papilloedema and/or a decreased level of consciousness. Patients with very dilated lateral ventricles did not in general have PVL, but it was frequently seen in association with diastasis of the sutures. Twelve patients with PVL had no other clinical or radiological indication of raised intracranial pressure. Comparison with the control cases did not reveal any reason as to why some patients should develop PVL while others did not.