This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'All are radiological features of Mitral stenosis except – \nSelect and explain. \nA. Straight left border of heart, B. Oligemia of upper lung fields, C. Pulmonary hemosiderosis, D. Lifting of left bronchus', 'role': 'user'}, {'content': "Answer: B \nExplanation: Radiological signs of mitral stenosis\n\nDue to left atrial enlargement:- Straightening of left heart border, elevation of left main bronchus with the widening of the carina, double atrial shadow (Double density sign), posterior displacement of the esophagus on barium swallow, Prominent posterosuperior part of the cardiac shadow.\nDue to pulmonary venous hypertension\xa0:- Diversion of blood flow from the lung bases to the upper zone (cephalization of pulmonary vascularity), pulmonary hemosiderosis, peribronchial cuffing, Kerley B lines and sometimes Kerley 'A' lines, perihilar haze, alveolar edema, small pleural effusion, pulmonary ossicles, fine punctate calcification in lung.\nDue to elevated pulmonary hypertension:- Enlargement of central pulmonary vessels with peripheral pruning.\n\n\nThere is increased blood flow (plethora) in upper lung fields due to the diversion of blood flow to the upper zone.", 'role': 'assistant'}]