Head and Neck ImagingMastoiditis
purulent effusion in the mastoid cavity secondary to acute
otitis media; an unusual finding since the advent of antibiotics. Progression to mastoid bone involvement, with destruction of the
intercellular septae and formation of pus-containing cavities, possibly with intra- and extracranial complications, is nowadays rare ('coalescent mastoiditis'). Coalescent mastoiditis is an indication for surgical drainage; the bone destruction is sometimes subtle and its demonstration requires high-resolution
CT (
Fig.1). Intracranial extension may be complicated by thrombophlebitis of the sigmoid
sinus.
Sometimes a subperiosteal abscess develops secondary to mastoiditis without visible bone destruction, presumably due to spread of disease via thrombophlebitis of small mastoid veins.
RH
To view high resolution images,
please register first.
Click
here
to register.
Already registered? Enter your e-mail in the window below.Re-registerFig.1
Axial CT images of temporal bones. The contrast-enhanced image shows a large extramastoidal abscess on the right side (a, arrows). The high resolution image reveals focal erosion of the lateral mastoid cortex (b). Arachnoid cyst (a, asterisk).
 | |  | |
Mastoiditis, Fig.1 (a) | | Mastoiditis, Fig.1 (b) | |