Densitometric evaluation of lung aeration in chest films

Lung aeration can be evaluated densitometrically from chest films, using a microscope with one eyepiece replaced by a photocell, and the attenuation of the pulmonary parenchyma can be assessed numberically, as a "radiologic expansion index". In premature rabbit neonates, this index was significantly increased among animals receiving a pharyngeal deposit of homologous lung surfactant before the first breath, as compared with untreated controls. This technique could in modified form be used for clinical purposes, such as the evaluation of lung aeration in newborn infants with respiratory distress.