Which radiological features are characteristic of emphysema?

Emphysema is a condition characterized by the destruction of alveoli, leading to an increase in the volume of air trapped in the lungs, which is seen on imaging studies. One of the hallmark radiological features of emphysema is the appearance of very black lungs on a chest radiograph. This increased radiolucency is due to the loss of lung tissue and the over-distension of air spaces, which allows more X-rays to pass through, resulting in a darker appearance.

Additionally, patients with emphysema often develop a barrel chest, which is a result of chronic over-inflation of the lungs. The rib cage becomes more rounded, resembling the shape of a barrel. This structural change is a compensatory mechanism as the lungs are chronically hyperinflated and the diaphragm function can be impaired.

The other options describe features not typically associated with emphysema. For instance, fluffy infiltrates and pleural effusion indicate infections or fluid accumulation rather than emphysema. Consolidation and nodularity suggest pneumonia or lung tumors, while increased vascular markings are often seen in conditions like congestive heart failure rather than emphysema, which typically shows diminished vascular markings due to the destruction of lung parenchyma. These distinctions are