Pericardial effusion - water bottle sign


It is always worth remembering that although many radiologists will report chest x-rays as "the cardiac outline is enlarged" or even "the heart is enlarged", this is not always the case. Epicardial, anterior mediastinal or intrapericardial conditions can all look very similar. 

In this case the patient had a large pericardial effusion, confirmed on echocardiography.