Measurements of regional cerebral blood flow in patients following superficial temporal artery-middle cerebral artery anastomosis.

Regional cerebral blood flow (rCBF) was measured using the inhalation xenon 133 technique in 25 patients undergoing superficial temporal artery-middle cerebral artery anastomotic surgery. rCBF was measured once before and 3 times after operation, up to one year. Data were compared to rCBF-measurement in 16 patients with similar diagnosis, age distribution and medical treatment except that they were not operated on. Mean rCBF increased in some patients 4-8 weeks after surgery on the ipsilateral side. Compared to the non-surgical patients mean rCBF at this time was higher over both hemipheres. However, taking a flow increase of at least 15% as being significant only one third of all patients presented with a significant flow increase. Regional flow data indicated that the amount of hypoaemic areas in the operated side decreased significantly. Areas with normal flow increased in number from CBF 1 to the 4-8th week. There were no significant changes in flow distribution over the contralateral side. It was concluded that extracranial-intracranial bypass improves flow in patients with TIA or PRIND respectively only in some cases. Also a return to normal flow distribution can be achieved in only a few cases.