This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory Radiology, Subject name: Radiology
'Batwing' appearance on X-ray chest is seen in: 
Select and explain. 
A. Bronchial asthma, B. Cardiogenic pulmonary edema, C. Mitral stenosis, D. Pulmonary embolism
B: Cardiogenic pulmonary edema
Answer: B: Cardiogenic pulmonary edema 
Explanation: In Cardiogenic pulmonary edema: "Butterfly" or "Bat wing" appearance (i.e., consolidated hilum + uninvolved lung coex) on CXR. The central/perihilar distribution is supposed to be due to increased fluid accumulation in central alveoli due to their increased elastin content. Chest radiograph shows: Cardiogenic pulmonary edema Non-cardiogenic pulmonary edema Enlarged cardiac silhouette Hea size is normal Vascular redistribution Alveolar infiltrates are distributed more uniformly Interstitial thickening and perihilar alveolar infiltrates Pleural effusions are common Pleural effusions are uncommon