CT of the feline nasopharynx for stertor

Why stertor in cats deserves a work-up

Stertor is a snoring sound from the upper airway. In 94 cats with upper respiratory tract disease that all had CT (Vekšins, Veterinary World, 2022), the most common CT findings were:

• rhinosinusitis (55.32%)
• nasal neoplasia (26.6%)
• nasopharyngeal polyp (14.89%)

Age helps. Cats with a polyp as the primary diagnosis were 3 months to 6 years old (mean 1.85 years), while cats with nasal neoplasia were 5 to 18 years old (mean 10.56 years).

The nasopharynx lies above the soft palate and cannot be seen in the awake cat.

What CT shows

Condition	What the evidence shows
Inflammatory polyp	In 13 cats (Oliveira et al., Veterinary Radiology & Ultrasound, 2012): after contrast, oval and well-defined with rim enhancement in all. A stalk ran through the auditory tube to an affected tympanic bulla in 11. Every cat had at least one severely affected bulla, and the medial retropharyngeal lymph node was enlarged in 8.
Nasopharyngeal stenosis	In 12 cats (Kang and Brash, Journal of Feline Medicine and Surgery, 2025): focal, abrupt narrowing by a soft tissue band, always in the caudal third of the nasopharynx. Mild contrast enhancement in 8 of 11, and the soft palate deviated dorsally at the stenosis in 8 of 12, best seen in the sagittal plane.
Lymphoma	The most common feline upper respiratory tract tumour (Santagostino et al., Veterinary Pathology). Of 39 cats, lymphoma was nasal in 26, nasopharyngeal in 6 and in both sites in 7.
Cryptococcosis	In a study of 12 dogs and 9 cats (Wong et al., American Journal of Veterinary Research, 2024), cats had more focal nasal and nasopharyngeal disease than dogs and were more likely to have a nasopharyngeal mass. Cribriform plate lysis was not seen in cats, and retropharyngeal lymph nodes were more likely enlarged.

Stenosis: what CT adds before treatment

In 23 cats with nasopharyngeal stenosis compared with 20 controls (Mestrinho and Fonseca, Journal of Small Animal Practice, 2024), affected cats:

• were younger
• had more paranasal sinus anomalies and shorter soft palates
• never had turbinate lysis

The stenosis ranged from a membrane to partial or complete adhesion of the soft palate, was mostly caudal, and was imperforate in about half. Imperforate membranes were thicker in the sagittal plane and were associated with nasal obstruction and soft tissue in the tympanic bulla.

Radiography, CT and nasopharyngoscopy

Lateral radiographs of the nasopharynx can screen for stenosis. In 52 cats with stertor (Masuyama et al., Veterinary Radiology & Ultrasound, 2025), radiography had 100% sensitivity and 83.9% specificity against rhinoscopy. The authors note that consensus reading may have overestimated accuracy, and that rhinoscopy remains the definitive test. The CT stenosis study also advises that suggestive CT features should prompt retroflex nasopharyngoscopy to confirm the diagnosis.

Nasopharyngeal CT protocol at a glance

Head CT shows the whole length of the nasopharynx, the nasal cavity in front of it and the tympanic bullae beside it in one study. Post-contrast images matter, because polyps showed rim enhancement after contrast, and the sagittal plane shows how the soft palate relates to a stenosis.

What the radiologist looks at

• The polyp pattern. The authors of the polyp study consider a well-defined mass with strong rim enhancement, a stalk-like structure and asymmetric thickening and expansion of the bulla highly indicative of an inflammatory polyp.
• The stenosis itself. Its position, length, thickness and perforate or imperforate appearance, which help plan treatment.
• The tympanic bullae. The nasopharynx and middle ear are linked: polyps reach the nasopharynx through the auditory tube. In 25 cats with inflammatory polyps (Hoppers et al., Veterinary Dermatology, 2020), 6 (24%) had bilateral polyps, and in 4 of those 6 the second polyp was found with advanced imaging at referral. In cats with stenosis, soft tissue material in the bullae was seen in 4 of 12.

What your report will include

Every Veheri case is read by a radiologist or neurologist, and when you order you can choose Diplomate-only reporting or the full specialist panel. You can chat directly with the specialist assigned to your case, and a simplified pet owner report helps you explain the findings to the owner.

When you take the report forward:

• A nasopharyngeal mass usually needs sampling, because CT does not give a histological diagnosis. In upper respiratory tract lymphoma, imprint cytology was diagnostic in 12 of 25 cases (48%), so histology may still be needed.
• A suspected stenosis is confirmed by nasopharyngoscopy, as both the CT and radiography studies advise.
• Location and type guide treatment. In 21 cats (Champetier et al., Journal of Feline Medicine and Surgery, 2024), balloon dilation brought complete resolution in 11 of 12. Surgery succeeded in 7 of 8; the one failure was a rostral stenosis. The authors recommend endoscopic treatment for perforate membranes.

What to include when you request a nasopharyngeal CT report

• signalment: age, breed and sex
• duration of stertor, and whether it is constant or intermittent
• nasal discharge, sneezing, otitis or vestibular signs
• previous upper respiratory infection
• previous polyp removal or nasopharyngeal procedures
• FeLV status and any cryptococcal test results

How Veheri can help

Veheri provides veterinary teleradiology for X-ray, CT and MRI, with expert support for CT scanning protocols, positioning and acquisition. Related reading: CT of the feline nasal cavity and CT of the feline middle ear.