Page 278 - Small Animal Internal Medicine, 6th Edition

250 PART II Respiratory System Disorders

COMPUTED TOMOGRAPHY AND
MAGNETIC RESONANCE IMAGING
VetBooks.ir CT provides excellent visualization of the nasal turbinates,
nasal septum, hard palate, and cribriform plate (Fig. 14.8).
In cats CT is also useful for determining middle ear involve-
ment with nasopharyngeal polyps or other nasal disease.
CT is more accurate than conventional radiography in
assessing the extent of neoplastic disease insofar as it allows
more accurate localization of mass lesions for subsequent
biopsy than nasal radiography, and it is instrumental for
radiotherapy treatment planning. Determination of the
integrity of the cribriform plate is important in treatment
planning for nasal aspergillosis. CT may also identify the
presence of lesions in animals with undiagnosed nasal
disease when other techniques have failed. Typical lesions
are as described in Box 14.1. MRI may be more accurate
than CT in the assessment of soft tissues, such as nasal
neoplasia.

RHINOSCOPY

Rhinoscopy allows visual assessment of the nasal cavity
through the use of a rigid or flexible endoscope or an oto-
scopic cone. Rhinoscopy is used to visualize and remove
foreign bodies; to grossly assess the nasal mucosa for the
presence of inflammation, turbinate erosion, mass lesions,
fungal plaques, and parasites; and to aid in the collection
of nasal specimens for histopathologic examination and
FIG 14.7 culture. Complete rhinoscopy always includes a thorough
Intraoral radiograph of a dog with nasal aspergillosis. Focal
areas of marked turbinate lysis are present on both sides of examination of the oral cavity and caudal nasopharynx,
the nasal cavity. The vomer bone remains intact.

F

E
T E
T

A B

FIG 14.8
Computed tomography scans of the nasal cavity of two different dogs at the level of the
eyes. (A) Normal nasal turbinates and intact nasal septum are present. (B) Neoplastic
mass is present within the right cavity; it is eroding through the hard palate (white arrow),
the frontal bone into the retrobulbar space (small black arrows), and the nasal septum.
The tumor also extends into the right frontal sinus. E, Endotracheal tube; F, frontal sinus; T,
tongue.