Cerebral fluid dynamics and brain regional blood flow in experimental hydrocephalus.

Cerebral blood flow was measured by the indicator fractionation technique in normal, acute hydrocephalic, chronic compensated hydrocephalic and craniectomized hydrocephalic cats. In the five normal cats the mean total brain blood flow was 136.1 ml/min/100 g dry weight. The six acute hydrocephalic animals demonstrated a relatively uniform 22% reduction in total blood flow. In eight chronic hydrocephalic cats CBF increased to the point where there was only an overall 7% decrease. In three hydrocephalic and craniectomized cats the CBF was reduced by 30.6%. In the acute phases there was a decrease in the number of blood vessels. Chronic compensated hydrocephalic brains had somewhat more vessels than the normal, whereas the craniectomized, massively hydrocephalic brain had a dramatic increase in both the number and caliber of blood vessels. These results clearly demonstrate that in acute obstructive hydrocephalus in cats, there is a significant decrease in CBF. The blood vessels revert to normal in shunted cats.