Computed tomographic features of suspected arterial pseudoaneurysm in the head and neck of four dogs.

Computed tomography is a valuable diagnostic technique in the clinical work-up of dogs with oropharyngeal trauma and bleeding. Traumatic extravasation can manifest as a pseudoaneurysm. A pseudoaneurysm is an extraluminal accumulation of blood that is contained by the adventitia layer or neighboring tissues. The purpose of this retrospective, multicenter, observational case series study was to describe the CT features in dogs with presumed oropharyngeal arterial pseudoaneurysm and its potential association with trauma. Imaging archives were searched for canine patients with head and neck CT studies showing visible extravasation of contrast-enhanced blood contained by soft tissue structures. Medical records of these patients were reviewed for oropharyngeal bleeding or trauma and reported. Four dogs met the inclusion criteria. CT findings included a well-defined, confined area of vascular contrast enhancement adjacent to the common carotid artery or its branches. The mean contrast enhancement in the corresponding artery and pseudoaneurysm lesion was similar, suggesting that these lesions represent active arterial extravasation. Four-dimensional CT was performed in one case and demonstrated contrast medium leaking from an artery and being contained by adjacent soft tissue structures. All dogs had a history and imaging findings consistent with oropharyngeal bleeding and trauma. Arterial pseudoaneurysm should be considered as a differential diagnosis in dogs with oral trauma and CT features of a well-defined, periarterial, strongly contrast-enhancing lesion.