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
Luftsichel sign is seen in 
Select and explain. 
A. Right upper lobe collapse, B. Right middle lobe collapse, C. Left upper lobe collapse, D. Left lower lobe collapse
C: Left upper lobe collapse
Answer: C: Left upper lobe collapse 
Explanation: Luftsichel sign is a sickle shaped lucency of air seen On Chest Radiographs, Seen in Left Upper lobe collapse with Compensatory Left Lower lobe hyperinflation.