Validation of an ultrasound imaging technique of the tympanic bullae for the diagnosis of otitis media in calves

Abstract

Background: Otitis media is a common disease in calves that can be subclinical, making antemortem on-farm diagnosis challenging.

Objectives: To evaluate the sensitivity and specificity of ultrasonography of tympanic bullae for the diagnosis of clinical and subclinical otitis media and to evaluate the reproducibility of the technique.

Animals: Forty calves 19-50 days of age were selected from a veal calf farm.

Methods: Prospective study. Ultrasonography was first performed on the farm by ultrasonographer A (US A). Ultrasonography was repeated by ultrasonographer A (US A') and another ultrasonographer (US B) at the Centre Hospitalier Universitaire Vétérinaire. Images were later reread by both examiners and a diagnosis was recorded. The calves were euthanized and submitted for necropsy, and histopathologic diagnosis was used as the gold standard.

Results: Forty-five bullae were affected by otitis media and 35 bullae were normal. Sensitivity and specificity of the ultrasound technique ranged from 32 to 63% and 84 to 100%, respectively, depending on the examiner and classification of suspicious ultrasonography results. Kappa analysis to evaluate interobserver agreement between A' and B yielded a к value of 0.53. Agreement within the same examiner (A versus A') yielded a к value of 0.48, and real-time ultrasound versus rereading of recorded images for A' and B yielded к values of 0.58 and 0.75, respectively.

Conclusions: Sensitivity and specificity of the ultrasound imaging technique are, respectively, low and high for diagnosis of clinical and subclinical otitis media in calves, with moderate reproducibility.

Keywords: Cattle; Middle ear; Prevalence; Subclinical; Ultrasonography.