The Effects of lodinated Contrast Agents on Autoregulation of Cerebral Blood Flow

Abstract

The effects of an iodinated contrast agent, Renografin-76® upon cerebral autoregulation was studied in rhesus monkeys. This was done by measuring the effects of an intravenous injection of Renografin-76 upon: (1) the response of baseline CBF as measured by the washout of a carotid bolus of H₂¹⁵O during and after the injection of Renografin-76, (2) the response of CBF monitored continuously by a Doppler flow probe technique to changes in the mean arterial blood pressure (MABP) before and after an injection of Renografin-76, and (3) the response of the regional cerebral blood volume (rCBV) as measured by stimulated x-ray fluorescence. An intravenous injection of Renografin-76 can disturb cerebral autoregulation in the rhesus monkey for as long as 15 minutes after the beginning of the injection. After the intravenous in jection of Renografin-76, transient rises in both CBF and MABP lasting from 2 to 12 minutes occurred on an average of 23% and 16%, respectively, over control values.