Acute otitis media is the most common local infection in children under 5years of age. This is because the adenoid tissue of the nasopharynx is hypertrophied in chil­dren and the Eustachian tube is obstructed by the accumulation of secretions due to its horizontal course [21]. Otitis media, usually of a bacterial origin, is an inamma­tion of the ME.CT scans show uid accumulation, thickening of the ME mucosa, and disruption of the ossicular chain. Acute otitis media presents with uid opaci­cation, while chronic otitis media (COM) shows ossicular erosion, bony destruc­tion, and cholesteatoma formation. Mastoiditis, an extension of otitis media, is characterized by bony erosion within the mastoid air cells, which can be seen on CT scans. In severe cases, imaging is helpful in determining the extent of bone destruc­tion and possible intracranial involvement [21, 22]. While the diagnosis of acute mastoiditis is based on clinical examination, imaging is required in chronic otomas­toiditis, especially in the setting of complications.If the infection is not controlled and secretions accumulate, the pressure in the ME cavity increases and the TM may perforate. This initiates a complex process leading to acidosis, decalcication, bone erosion, and ischemia. Subsequently, the walls of the mastoid air cells are destroyed and coalescent mastoiditis develops. In acute coalescent mastoiditis, the thin bone septa between the mastoid air cells are lysed by the infection, and this destruction is seen on CT as a loss of density in the trabeculae. If the purulent material passes through the periosteum to the emissary veins, a subperiosteal abscess may be seen (Fig. 5.9) [21]. This was described as Bezold’s abscess in 1908. If the infection causes destruction of the sigmoid sinus plate, an epidural abscess may occur, and, if it causes a defect in the tegmen, the infection may spread to the middle cranial fossa [21, 22].