Regional cerebral blood flow in the rat as determined by particle distribution and by diffusible tracer

Measurements of total and regional cerebral blood flow in paralyzed rats maintained on 70% N2O/30% O2 obtained by a diffusible tracer technique, iodoantipyrine, and by a particle distribution method, microspheres, have been compared. Total CBF values were in good agreement, 0.86 +/- 0.07 ml/g/min (PaCO2 37.3 +/- 1.5, iodoantipyrine method) and 0.88 +/- 0.02 (PaCO2 36.2 +/- 0.8, microsphere method). Regional cerebral blood flows showed good agreement with the 2 methods, with highest flow in the colliculi, striatum and cerebral cortex and lowest flows in the hypothalamus, pons medulla and cerebellum. The iodoantipyrine method is technically easier to perform and had a higher precision.