CT scan signs of confirmed nasopharyngeal narrowing in 12 cats

Abstract

OBJECTIVES: CT is frequently utilised in the assessment of upper respiratory tract disorders. The aim of the present study was to further describe the CT features in cats with confirmed nasopharyngeal stenosis (NPS). METHODS: CT images of the heads of cats with NPS confirmed via retroflex nasopharyngoscopy between 2011 and 2023 were retrospectively reviewed to describe the imaging features of NPS and other concurrent findings. RESULTS: In total, 12 cats were included. All but one cat had pre- and post-contrast images available. All CT studies demonstrated focal, abrupt narrowing of the nasopharyngeal lumen by a variably thickened, homogeneous, soft tissue attenuating band. One cat appeared to have two separate NPS, giving a total of 13 NPS. All NPS were located in the caudal third of the nasopharynx, which resulted in a marked reduction in the luminal cross-sectional area. The narrowing of the nasopharyngeal lumen was either concentric (11/13) or lateral-to-lateral (2/13). Mild homogeneous contrast enhancement of the soft tissue band was observed in 8/11 cats (73%). The soft palate was focally dorsally deviated at the NPS site in 8/12 cats (67%) and was best seen in the sagittal plane. Other concurrent findings included non-contrast-enhancing soft tissue attenuating material within the nasal cavity (7/12) and tympanic bullae (4/12), and mild medial retropharyngeal lymphadenomegaly (2/12). CONCLUSIONS AND RELEVANCE: The most frequently observed CT features in cats with NPS are marked, focal, abrupt narrowing of the nasopharyngeal lumen by a mildly contrast-enhancing soft tissue band in the caudal third of the nasopharynx and focal deviation of the soft palate dorsally at the NPS site. Identifying any of these CT features in the presence of compatible clinical signs should prompt further evaluation with retroflex nasopharyngoscopy to confirm the diagnosis of NPS and to direct appropriate treatment.