A Comparison Of The Rostrocaudal Open Mouth And Rostro 10° Ventro-Caudodorsal Oblique Radiographic Views For Imaging Fluid In The Feline Tympanic Bulla

Gawain J. C. Hammond, Martin Sullivan, Steven Weinrauch, et al.

Veterinary Radiology & Ultrasound 2005;46:205-209.

Fluid within the tympanic bulla is an indication of middle ear disease. Radiography has a relatively low accuracy for the detection of soft tissue opacification in the tympanic bulla, and the most useful radiographic projection, the rostrocaudal open mouth (RCd (open mouth)), is technically difficult to perform in dogs and cats. An alternative projection for the feline tympanic bulla, the rostro 10 degree ventro-caudodorsal oblique (R10 degree V-CdDO), was compared to the RCd (open mouth) in 41 feline cadaver heads with the tympanic bullae randomly filled with KY jelly. Computed tomography was used as the gold standard. Each tympanic bulla was recorded as being positive or negative for soft tissue opacification. Although there was no significant difference between the accuracy of the two views, the R10 degree V-CdDO was subjectively more accurate and easier to perform, and in a live patient may be performed without the need for general anesthesia. The R10 degree V-CdDO projection is a good alternative to the RCd (open mouth) projection for detecting otitis media in the cat.