Comparison of ultrasonography, radiography and a single computed tomography slice for fluid identification within the feline tympanic bulla.

Evaluation of the tympanic bulla (TB) in cases of acute feline otitis media can be a diagnostic challenge, although a feature often associated with this condition is the accumulation of fluid or material within the middle ear cavity. A technique is reported allowing optimum imaging of the feline TB using ultrasound (US) and recording of the appearance of gas and fluid-filled TB. A random number of bullae in 42 feline cadavers were filled with lubricant and rostroventral-caudodorsal oblique radiographs, single slice computed tomography (CT) images and US images were created and interpreted by blinded operators. The content (fluid or gas) of each TB was determined using each technique and the cadavers were then frozen and sectioned for confirmation. CT remained the most accurate diagnostic method, but US produced better results than radiology. Given the advantages of US over other imaging techniques, these results suggest that further work is warranted to determine applications of this modality in the evaluation of clinical cases of feline otitis media.