This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
A 45-year-old man presents with exertional dyspnea and pitting pedal edema. His neck veins are dilated. A diagnosis of superior vena cava (SVC) syndrome is made. What will you do next? 
Select and explain. 
A. Do total blood count and peripheral smear, B. Do a CT chest, C. Start cyclophosphamide, D. Start radiotherapy
B: Do a CT chest
Answer: B: Do a CT chest 
Explanation: ANS. BThis shows an approach to a case of SVC syndrome which clearly says that first step is CT chest with contrast. This helps us to arrive at a cause for SVC syndrome and treat accordingly.Various causes of SVC syndrome are: