X-ray examination of intracranial blood vessels after injection of radiopaque dye into the neck (carotid) artery. Whether arteries or veins are visualized depends on how long the film is exposed after the injection. Cerebral angiography detects solid lesions by showing blood-vessel deformities or displacement. It reveals areas without blood vessels, where cysts and abscesses of the brain are likely to exist. The process was introduced and developed between 1927 and 1937 by António Egas Moniz. See also brain scanning; echoencephalography; diagnostic imaging.