Which radiographic finding is most characteristic of a pericardial effusion?

Which radiographic finding is most characteristic of a pericardial effusion?

• A. Pulmonary edema
• B. Normal cardiac silhouette
• C. Water bottle-shaped cardiac silhouette
• D. Kerley B lines

Answer: (C)

When fluid collects around the heart, it expands the cardiac silhouette in a distinctive way. The classic radiographic sign of a sizable pericardial effusion is a round, globular heart that looks like a water bottle or flask—the water bottle-shaped cardiac silhouette. This occurs because the heart is encased in a fluid-filled pericardial sac, making the overall shape of the heart appear more uniform and enlarged on the film. Other findings point to different processes. Pulmonary edema causes interstitial and/or alveolar markings in the lungs and signs like Kerley B lines, reflecting fluid in the lung tissue rather than around the heart. A normal cardiac silhouette can occur with small effusions or early disease, but it is not the characteristic feature of a pericardial effusion.

When fluid collects around the heart, it expands the cardiac silhouette in a distinctive way. The classic radiographic sign of a sizable pericardial effusion is a round, globular heart that looks like a water bottle or flask—the water bottle-shaped cardiac silhouette. This occurs because the heart is encased in a fluid-filled pericardial sac, making the overall shape of the heart appear more uniform and enlarged on the film.

Other findings point to different processes. Pulmonary edema causes interstitial and/or alveolar markings in the lungs and signs like Kerley B lines, reflecting fluid in the lung tissue rather than around the heart. A normal cardiac silhouette can occur with small effusions or early disease, but it is not the characteristic feature of a pericardial effusion.