Imaging in the evaluation of emphysema

The role of imaging in the assessment of emphysema has assumed increased importance since the advent of surgery as one of the potential therapeutic options. The chest radiograph had tended to be dismissed because it did not correlate well with pulmonary function tests, but pulmonary function tests may be normal in mild emphysema.1 The chest radiograph may be normal too, but more often in chronic bronchitis than in true emphysema. Signs of hyperinflation include a flattened diaphragm, particularly one depressed to the level of the seventh rib anteriorly or below, while on the lateral film there may be an increased anteroposterior diameter of the chest and increased retrosternal and retrocardiac lucency. Other signs of emphysema include peripheral pruning of vessels, although this is lost with the onset of cor pulmonale when the vessels appear to become more numerous and larger.2 3 Ventilation and perfusion isotope scanning have been used for some years to assess patients with limited cardiorespiratory reserve undergoing …