a) In the diseased ear: 24 cases out of 50 (48%) had well pneumatized mastoid air cell
system in the diseased ear as opposed to 26 cases (52%) that had poor pneumatization.
Among the pneumatised mastoids on HRCT, different type of mastoid air cell
groups observed were squamomastoid type of air cells in all, with perilabyrinthine type of air cells in 25%, petrous apex pneumatisation in 10% and accessory pneumatisation in 25%.
The other theory of development of the mastoid air cell
system suggests that the precursors of the mastoid cells are present at birth as periantral, mesenchyme-filled loculi that are visible on histologic sections.
Aeration was most commonly to the level of the mastoid air cells
in all age groups.
A unilocular ZACD appears as radiolucency with well defined borders, while the multilocular type demonstrates numerous small cavities within, which resemble mastoid air cells
A transverse fracture through the external ear and mastoid air cells
CSF leaks results from a communication way that takes place between the subarachnoid space, the mastoid air cells
, the middle ear, the petrous apex air cells, and finally either the Eustachian tube (ET), the surgical incision, or a tear in the tympanic membrane [7-10, 12-17].
Evidence of poor pneumatisation of mastoid air cells
on left side.
This can be accompanied by a concomitant shading of the mastoid air cells
, which could manifest as a reduced opacity on computed tomography (CT) in the absence of a history of chronic mastoiditis or acute inflammatory signs.
mastoid air cells
and the temporal bone with/without involvement of
Computed tomography (CT) (Figs 1a, b and c) of the brain showed a large, destructive lesion in the left ear cavity, extending anterior to the pre-auricular region and posterior to the mastoid air cells
Computed tomography (CT) showed partial opacification of the left mastoid air cells
and middle ear cavity and thickening of the left tympanic membrane and skin of the left EAC.
In majority of the poorly or acellular mastoid, sclerosis of the mastoid air cells