Page 60 - Feline diagnostic imaging

56 5 Diagnostic Imaging of Diseases of the Skull

(a) (b) (c)

(d) (e) (f)

Figure 5.8 Intraoral mandibular radiographs of a cat with squamous cell carcinoma (a–c, arrows) and osteomyelitis (d–e, arrows).
Squamous cell carcinoma is the most common oral neoplasm and extensive osteolysis and irregular mineral margins are commonly
seen. The teeth in some areas appear to float, which is the result of teeth embedded with neoplastic tissue. Because mandibular
osteomyelitis has similar radiographic features to neoplasia, it is important to obtain samples for definitive diagnosis. The extent of a
lesion, such as a mandibular squamous cell carcinoma, can be seen in skull radiographs (f). The right mandible is more ventral than
the left on this oblique view. Source: Images courtesy of Dr Anthony Fischetti, Animal Medical Center, and Dr Shannon P. Holmes,
Animal Cross‐Sectional Imaging Specialists.

the nasal cavity can be evaluated but only if the patient’s imaging for nasal disease. It has demonstrated increased
mouth is maximally opened. As mentioned, subtle sensitivity for differentiating inflammatory from neoplas-
obliquity of the VD or DV skull radiograph can artifactu- tic conditions, detecting nasal foreign bodies and for
ally increase the opacity in the nasal cavities. Increased localizing the disease process as well as the extent of dis-
opacity is a primary finding in most feline nasal disease ease [34]. Therefore, CT has an important role in deter-
and thus poor radiographic technique could result in mining sampling options and planning surgery. The
misdiagnosis. Finally, the radiographic features of primary diseases affecting the nasal cavity of feline
benign and aggressive nasal disease processes overlap patients that are evaluated with diagnostic imaging are
significantly. These include opacification of the air‐filled rhinitis and neoplasia.
spaces of the nasal cavity and sinuses, nasal turbinate Rhinitis or rhinosinusitis denotes inflammation of the
destruction, soft tissue enlargement or mass effect or nasal passages. The inflammation may be due to underlying
lysis of the bone surrounding the nasal cavities and infection, immune‐mediated cellular infiltration or, uncom-
sinuses. Unilateral disease or disease causing loss of monly, foreign body reaction. There are some forms of infec-
teeth is more suspicious for neoplasia [33]. CT examina- tious rhinitis that may not necessitate imaging and are
tions of this area are more common than MRI; this is treated empirically; the most common of these are acute
suspected to be because CT is more available and costs viral and bacterial infections. Chronic inflammatory/infec-
less than MRI. Also, CT requires less time which is tious and fungal rhinitis are the cases that are more fre-
important should the patient require surgery following quently imaged. Chronic rhinitis is common, accounting for
imaging and CT is useful for radiation therapy planning approximately 35% of feline cases of rhinitis [3, 35, 36]. The
in the event of neoplasia. radiographic features of chronic rhinitis include unilateral
Nasal disease identification with MRI is mostly seen in or bilateral soft tissue opacification of the nasal passages as
feline patients presenting with intracranial signs, as dis- well as the frontal sinuses and variable nasal turbinate
cussed in Chapter 6. CT is currently the preferred mode of destruction that depends on the severity and chronicity [33].