This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiology Q Bank, Subject name: Radiology
Which of the following causes BOTH superior and inferior rib-notching in a chest radiograph? 
Select and explain. 
A. NF-1, B. Blalock Taussig shunt, C. SVC occlusion, D. Coarctation of aoa
A: NF-1
Answer: A: NF-1 
Explanation: Superior rib notching -Polio -Restrictive lung disease -Neurofibromatosis -Connective tissue disease -Osteogenesis imperfecta Inferior rib notching -Thrombosis of aoa -Coarctation of aoa -Blalock Taussig shunt -Occlusion of subclan aery -Pulmonary AV malformation Both Superior and inferior rib notching -NF-1 -Hyperparathyroidism