Pulmonary fluid volumes (PBV = lung blood volume; EVLW = extravascular lung water) were examined to define the effects of oleic acid injury and then to examine the relationship between edema formation and accumulation of pulmonary thallium. In six dogs, pulmonary fluid compartments were monitored during the induction of pulmonary injury by oleic acid (0.15 cc/kg i.v.). By 30 min after the injection, EVLW had doubled (p less than 0.01); it continued to increase slowly for 180 min, whereas PBV declined. In six anesthetized dogs, we made similar measurements in an identical preparation and compared pulmonary fluid volumes with pulmonary counts derived from sequential thallium (1-1.3 mCi) scintigrams obtained after the injection of oleic acid (0.12-0.15 ml/kg). Measures of EVLW and PBV were obtained sequentially along with thallium scintigrams. There was a linear relationship between EVLW and pulmonary counts alone, or when pulmonary counts were normalized to myocardial activity. We conclude that sequential thallium scintigrams provide useful information about the degree of change of EVLW over time in a model of noncardiogenic pulmonary edema.