<prompt> Essential radiological feature of acute mastoiditis is:Temporal bone pneumatizationClouding of air cells of mastoidRarefaction of petrous boneThickening of temporal bone  <response>: b Clouding of air cells of mastoidRef. Cummings, 6th ed., 2161X-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. 