CT-Clinical Dissociation and Focal Obstruction in Feline Chronic Rhinosinusitis: A Pilot Study

Feline chronic rhinosinusitis (CRS) is common and difficult to manage, and the relationship between computed tomography (CT) findings and clinical severity remains unclear. This exploratory retrospective pilot study included 10 cats with chronic upper respiratory signs for at least 4 weeks that underwent CT of the nasal cavity and paranasal sinuses at a single referral hospital. Newly developed, unvalidated semiquantitative scores graded CT severity (0-12) and clinical severity (0-12), and cats were grouped into four provisional clinicoradiologic patterns using integrated CT, clinical, and cytologic findings and, where available, microbiologic findings. CT scores ranged from 2 to 10 (median 8.0) and clinical scores from 4 to 11 (median 6.5), without a consistent monotonic association (Spearman r_s = 0.250, 95% bootstrap confidence interval (CI) -0.558 to 0.885, p = 0.486). The provisional patterns were active/exudative (n = 2), structural/remodeling (n = 4), obstructive (n = 3), and immune/mucosal (n = 1). Focal obstruction defined both the obstructive pattern and the conceptual surgical candidacy categories, so their overlap is by design; of interest is that cats with the highest CT scores did not necessarily have focal obstruction. No cat underwent surgery. These hypothesis-generating findings require validation in larger prospective studies with validated scores.