[Computer tomographic diagnosis of lung abscess and pleural empyema]

Lung abscesses are characterised by irregular air spaces with non-homogeneous necrosis. Pleural empyemas often assume a sickle shape up against the thoracic wall and tend to be homogeneous. Problems in differential diagnosis may occur if the process is not confined to an exact anatomic position. A peripheral perforating abscess is isolated from the tracheobronchial system by thickened pleura and by its capsule; even if computer tomography does not show clear-cut findings, operative intervention is indicated.