High-resolution CT scan (axial cut) of the temporal bone. Total opacification of the left-sided hypo- and mesotympanum by a soft tissue density. Mastoid air cells totally opacified with resorption of septae and partially sclerosed bone. Partial dehiscence of the mastoid portion of the facial nerve canal. The left tympanic membrane is thickened and retracted inwards. The left middle ear ossicles and scutum are intact. Normal aeration of the external auditory canals with intact bony and cartilaginous boundaries. The right middle ear cavity is normally aerated with intact ossicles. The right mastoid air cells are unremarkable.