Pulmonary excretion of carbon black injected into the cerebral ventricles of the rat.

After injection of a mixture of carbon black and a iodinated X-ray contrast medium into the cerebral ventricles of rats carbon black loaded macrophages were found in the alveolar septa in the lungs. It is concluded that contrast media used in cerebral ventriculography are eliminated at least partly by discharge of pulmonary macrophages.