Studies of cerebral circulation time in man: 1 Normal values and alterations with cerebral vascular disease and tumour in arm-to-retina circulation times

The delay in filling is probably due to slowing of the cerebral circulation and in some cases it has been necessary to delay exposure of radiographs for one to five seconds in order to obtain satisfactory visualization of the intracranial vessels. Such prolongation of the circulation time, demonstrated arteriographically, has now been confirmed in some of our cases of cerebral vascular disease by the use of the Sanchez- Perez serial casette changer and a timing device. Slowing of the cerebral circulation time has also been shown following experimental cerebral em- bolism or occlusion of the middle cerebral artery (Meyer, 1958; Meyer, Gotoh, and Tazaki, 1962).