title: A simple way to estimate the size of a pneumothorax.
abstract: An approximate formula relating the volume of a pneumothorax to the decrease in linear dimensions of the lung is presented. For a small pneumothorax, the fractional volume occupied by pneumothorax is three times the fractional decrease in linear dimensions of the lung. These relationships were demonstrated with a simple phantom.
mesh_terms: D006801:Humans; D008961:Models, Structural; D011030:Pneumothorax / Q000000981:diagnostic imaging*; D011859:Radiography; D013679:Technology, Radiologic