Which radiographic feature is commonly seen on chest X-ray in cystic fibrosis?

• A. Translucent (dark) lung fields
• B. Elevated diaphragms
• C. Right ventricular enlargement
• D. Areas of atelectasis and fibrosis

Answer: (A)

Hyperinflation from mucus obstruction is a hallmark radiographic finding in cystic fibrosis. When small airways are blocked, air trapping occurs, especially during expiration, causing the lungs to appear more lucent (darker) on the chest X-ray. The diaphragms often look flattened as a secondary sign of this overinflation, but the defining feature is the translucent lung fields due to increased air in the lungs.

Elevated diaphragms can accompany hyperinflation, but they are not as specific or universal a sign as the overall increased lucency from air trapping. Right ventricular enlargement is a late finding tied to long-standing or severe disease with cor pulmonale, not a common early indicator. Areas of atelectasis and fibrosis can occur as the disease progresses or with mucus plugging, but the most consistent and characteristic radiographic change seen across many CF patients is hyperinflation with darker lungs.