Oto Primary Care FINALhigh

77 / 140

75
How to Read a Sinus CT Scan
sinuses above, and sphenoid sinuses
behind. You should carefully study every
x-ray, MRI, or CT scan that you encoun-
ter, so you can learn to recognize com-
mon anatomic variants and distinguish
them from true pathology. Here are
three common anatomic variants
encountered on coronal CT scans of the
sinuses.
Deviated nasal septum •
Asymmetry of sinuses, including size, •
shape, presence of septas, etc.
An air cell within the middle tur- •
binate (concha bullosa)
Abnormalities include fluid, mucosal
thickening, bony fractures, cysts, and
tumors, as shown in Figures 11.1 and
11.2.
The Osteomeatal Complex
The most significant area to examine in
a patient with sinus complaints is the
osteomeatal complex (OMC). Coronal
CT scans are used in the evaluation of
sinus disease because they are best for
visualizing the OMC. The OMC is the
region through which the maxillary, eth-
moid, and frontal sinuses drain in the
nose. An obstruction of the OMC will
frequently lead to sinusitis, and is often
due to mucosal edema or anatomic
abnormalities. Neoplasm should always
be on the differential diagnosis.
The anterior-most ethmoid sinus—the
agger nasi cell—is frequently clouded.
Edema in this sinus may be associated
with obstruction of the nasal frontal
duct and results in frontal sinusitis. This
Figure 11.1.
A coronal CT scan of the sinuses in a
patient with deviated nasal septum and an
air cell (concha bullosa) within the right
middle turbinate. The surgical correction of
nasal obstruction in this patient would
require partial middle turbinectomy, as well
as correction of the deviated nasal septum.
Figure 11.2.
A coronal CT scan of the sinuses
demonstrating complete opacification of the
nasal cavity and ethmoid and maxillary
sinuses. This image represents pansinusitis
with polyps; however, neoplasms may
present in a similar fashion.