[Sonographic measurement of soft-palate thickness and comparison with the measurement by computed tomography]

The aim of this study was to measure the thickness of the soft palate at specific locations in normocephalic dogs using sonography and computed tomography (CT), and to subsequently compare the two different methods.

A total of 15 normocephalic dogs were examined under general anesthesia. The CT was performed while patients were in a sternal recumbent position, their mouth held open by placing their upper jaw on a positioning device. Dorsal recumbency together with submental and midsagittal positioning of the transducer were chosen for sonography. Measurements were made in both sonographic and reconstructed sagittal CT images. Two measuring points (MP) were defined for measuring the cranial and the middle part of the soft palate (MP1: 1 cm caudal to the transition from the hard to the soft palate; MP2: at the origin of the dorsal pharyngeal muscles). It was investigated whether repeated procedures with one measuring method provided consistent values and, furthermore, whether the two different measuring methods (sonography and CT) provided comparable data.

The data acquired by repeat measurements within one method corresponded very well. However, the data provided by the two different measurement methods showed varying results for the first measuring point and was even greater for the second measuring point. Sonography overestimated the measurements obtained by CT by up to 0.26 cm for MP1 and up to 0.79 cm for MP2.

Due to the significant discrepancies in their results, the two measurement methods are not interchangeable. Sonography showed good reliability for repeat measurements. Consequently, the variable values between CT and sonography appeared to result from differing examination conditions. Sonography may be a rapid and non-invasive diagnostic tool to measure soft palate thickness if the applied method proves to be applicable in clinical practice.