This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Middle Ear (Otitis Media), Subject name: ENT
Essential radiological feature of acute mastoiditis is: 
Select and explain. 
A. Temporal bone pneumatization, B. Clouding of air cells of mastoid, C. Rarefaction of petrous bone, D. Thickening of temporal bone
B: Clouding of air cells of mastoid
Answer: B: Clouding of air cells of mastoid 
Explanation: (b) Clouding of air cells of mastoid(Ref. Cummings, 6th ed., 2161)X-ray mastoid and CT scan shows clouding of air cells because of the collection of exudates in them. Later on mastoid pneumatisation is lost and a single mastoid cavity may be seen.