On Computed tomographic scan, empyema is seen as a lung mass whose cavity is regular with smooth and regular lumen and well-defined boundary. The shape changes with change in patient’s position.^[1] Mass on CT scan may resolve on antibiotics. The split pleura sign on CT scan is present (most reliable sign to differentiate empyema from lung abscess where it is absent).^[2][3]

On Computed tomographic scan, empyema is seen as a lung mass whose cavity is regular with smooth and regular lumen and well-defined boundary. The shape changes with change in patient’s position.^[1] Mass on CT scan may resolve on antibiotics. The split pleura sign on CT scan is present (most reliable sign to differentiate empyema from lung abscess where it is absent).^[2][3]

CT of the chest demonstrates a very large right sided pleural collection with
thickened surrounding pleura (the so called split pleura sign) and multiple
gas bubbles. The adjacent lung is compressed and collapsed^[4]

The following image shows a CT scan of a pneumothorax caused by a pleural empyema.