This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiac and Pericardiac Imaging, Subject name: Radiology
[{'content': 'Double atrial shadow in mitral stenosis due to - \nSelect and explain. \nA. Left Atrial enlargement, B. Right Atrial enlargement, C. Tumor in Right Atrium, D. Right Atrium appendages.', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Left Atrial enlargement Sings of left atrial enlargementStraightening of left heart border (due to enlargement of left atrial appendage).Elevation of left main bronchus with widening (Splaying) of carina.Double density (atrial) sign.Posterior displacement of esophagus on barium swallow.Prominent posterosuperior part of cardiac shadow.", 'role': 'assistant'}]