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Figure 5b.  Petrous apicitis in a 7-year-old girl with fever, right-sided facial pain, and diplopia. (a) Axial CT scan of the temporal bone shows increased attenuation of the mastoid air cells and erosion of the right petrous apex (arrow) with a well-pneumatized left petrous apex. (b) Axial contrast-enhanced CT scan obtained with the soft-tissue algorithm shows a hypoattenuating area (arrow) without a significant enhancing soft-tissue mass. (c, d) Axial T1-weighted (c) and T2-weighted (d) MR images show a lesion (arrow) with low (c) and high (d) signal intensity. The patient was treated with mastoid drainage and intravenous antibiotics. (e) Follow-up axial CT scan shows postmastoidectomy changes and progressive reossification of the right petrous apex.