What will a chest X-ray show in a patient with an aortic dissection?

• A. Widened mediastinum
• B. Normal heart size
• C. Left basilar atelectasis
• D. Pleural effusion

Answer: (A)

A widened mediastinum on chest X-ray is the best clue for an aortic dissection. The dissection creates hemorrhage within the aortic wall and stretches the mediastinal structures, making the silhouette of the mediastinum appear enlarged on the film. This finding is the classic radiographic cue that raises suspicion and prompts definitive imaging, such as CT angiography. Other findings like a normal heart size, left basilar atelectasis, or a pleural effusion are not specific to dissection and can occur with many other conditions, so they don’t point as directly to this diagnosis. Remember, chest X-ray can be normal in some cases, but when present, mediastinal widening is the most informative sign.