Neuroradiology Case of the Week

Case 35

Francisco Garcia-Morales, MD, José A Echeverri, MD,
and P-L Westesson, MD, PhD, DDS

Clinical Presentation: Patient is a 12-year-old boy with chronic mastoiditis and a recent history of bilateral otitis media with otorrhea.

Radiological Findings: The middle ears are well aerated. Tympanostomy tubes, also called pressure-equalization tubes are present bilaterally in normal position (Figs. 1& 2).

Figure 1: Axial CT shows tympanostomy tubes in place (arrows). There is discrete mucosal thickening in posterior mastoid cells (arrowheads); otherwise relatively well aeration of the mastoid cell system is noted bilaterally.

Figure 2: Direct coronal CT shows the normal position of the left tympanostomy tube (arrow).

Diagnosis: Bilateral tympanostomy tubes in place with no evidence of serous otitis media.

Discussion:
   Chronic otitis media with effusion is an accumulation of inflammatory effusion in the middle ear and a frequent sequela of acute otitis media or serous otitis. Serous otitis media is associated with malfunction or obstruction of the eustachian tube. Tubal patency may be compromised by mucosal edema secondary to rhinopharyngitis, allergy or neoplasm [1].
   Effusions can occur anywhere in the middle ear cleft (tympanic cavity) or within the attic, antrum, or mastoid air cell system. Tympanostomy tubes (pressure-equalization tubes) are used in these patients both for drainage and normalization of intratympanic pressure. These tubes are made of various plastics and metals, including stainless steel and are consistently seen at CT. The tubes tend to be spontaneously extruded from the tympanic membrane after 3 to 6 months.

References:

1. Som PM, Curtin HD. Head and Neck Imaging, 4th edition, St. Louis, Missouri: Mosby, 2003; 1183-1185.