The palatovaginal canal: can it be identified on routine CT and MR imaging?

The palatovaginal canal is a short bone tunnel that extends from the pterygopalatine fossa to the roof of the pharynx. The primary purpose of our work was to establish whether the palatovaginal canal can be identified on CT and MR imaging. The secondary goal was to establish the frequency of visualization and the appearance of this canal.

We retrospectively analyzed 150 consecutive direct coronal CT studies obtained for evaluation of the sinonasal cavities. Frequency, bilaterality, and appearance of the palatovaginal canals were recorded. The frequency of the vidian canals was recorded for comparison. We also analyzed 20 MR imaging studies of that area to assess visualization of the palatovaginal canals and their contents. A dry skull specimen was examined using CT, and the images were correlated with those obtained in vivo.

The palatovaginal canal could be identified on CT on at least one side in 88 (58.7%) of 150 patients. Unilateral complete canals were found in 14 patients (9.3%), and unilateral semicanals were evident in 17 (11.3%). Bilateral complete canals were seen in 24 patients (16%), and bilateral semicanals were found in 11 (7.3%). In 22 patients (14.7%), one complete canal and one semicanal were detected. Fifty-five percent of the visualized canals were completely formed. The palatovaginal canal and its internal tubular structure, presumably corresponding to the pterygovaginal artery, were depicted on 40% of the MR imaging studies. The position and configuration of this canal as seen on CT of the dry skull specimen correlated well with the imaging findings.

The palatovaginal canals are commonly depicted on CT and MR imaging.