Regional extravascular lung water (rELW) and blood volume (rBV) in five controls and 14 patients with congestive heart failure (CHF) were measured by constant infusion of H215O and inhalation of 11CO using positron emission tomography (PET). The analysis of 18 regions per patient revealed a relatively homogeneous level of rELW in the controls (mean = 0.11 +/- 0.02 g/cc; range, 0.08-0.21), whereas this increase in patients with CHF (0.17 +/- 0.02 g/cc; range, 0.10-0.51). The rBV was 0.21 +/- 0.02 g/cc in the controls and 0.17 +/- 0.02 g/cc in patients with CHF. A good correlation was found between the severity of chronic heart failure (according to the grading of the New York Heart Association) and mean extravascular lung water (ELW) (r = 0.69), as well as between CHF and the ratio rELW/rBV (r = 0.87); however, the correlation to hemodynamic data was less satisfactory (cardiac index, r = 0.45; pulmonary capillary wedge pressure, r = 0.47; ejection fraction, r = 0.60). In supine controls, a progressive decrease in regional blood volume from the basal to the apical regions was observed, whereas the differences in ELW were only small. In patients with chronic heart failure, ELW in the basal parts was markedly increased, whereas in the apical regions, only minor deviations from the controls were observed. In the basal regions of these patients, the blood volume was reduced by about 30%. Instead of the normal basoapical gradient of blood volume, these patients showed a rather flat distribution. Radiographic findings of pulmonary edema generally appeared together with an ELW level of greater than 0.14 g/cc.(ABSTRACT TRUNCATED AT 250 WORDS)