Figure 3. Case 3 – Imaging of the petrous bone in a patient with left malignant otitis externa: axial unenhanced CT scan (A) showed stenosing soft tissue thickening of the left external auditory canal, with partial secondary opacification of mastoid air cells and focal erosion of the anterior canal wall (black arrow); multi-planar unenhanced MRI (B, C) showed complete opacification of mastoid air cells (B) and inhomogeneous diffusion signal restriction within retro- and para-pharyngeal soft tissue (C). After contrast administration, MRI (D–F) revealed intense enhancement of retropharyngeal, carotid and para-pharyngeal spaces, with initial involvement of masticator space and retro-condylar soft tissues (white arrows); internal carotid artery and internal jugular vein were patent, with reduced diameter compared to the opposite side (dotted line) due to external compression. Spongious and cortical clivus signal alteration was consistent with incipient skull base involvement (white arrowhead).