[The effect of piracetam on global and regional cerebral blood flow in acute cerebral ischemia of man (author's transl)].

Regional cerebral blood flow (rCBF) was investigated in 18 patients with acute cerebral ischemia by the intraarterial 133Xenon clearance method using a 10-detector-equipment. Intravenous administration of 6-10 g Piracetam caused an overall increase of the fast component of rCBF after 30 minutes corresponding to blood flow in the grey matter, of 10.0 ml/100 g/min (18.9%). The slow component of rCBF corresponding to the cerebral blood flow in the white matter remained unchanged. The regional CBF was influenced to a varying degree, the areas marked by an insufficient blood supply showing a mean increase by 17.5% and the areas marked by normal basic values showing a mean increase by 6.3%. This difference in alteration is statistically significant (p is less than 0.005) comparing the differences as %. The increase of cerebral blood flow in grey matter is interpreted as a secondary effect after activation of central nervous system metabolism by Piracetam.