Canine and feline abdominal arterioportal communications can be classified based on branching patterns in computed tomographic angiography

Arterioportal vascular anomalies are communications between the splanchnic arteries and the portal system that represent a rare cause of presinusoidal portal hypertension in small animals. There is little information concerning the imaging findings of arterioportal communications in small animals and no classification could be found for radiologists and surgeons. The aims of this retrospective descriptive multicentric study were to describe the computed tomographic (CT) characteristics of arterioportal communications in a group of cats and dogs, and to propose a classification based on CT angiographic anatomy. Computed tomography databases from multiple veterinary hospitals were searched for cats and dogs with a diagnosis of arterioportal communication. A total of 36 animals (33 dogs, 3 cats) met the inclusion criteria. There were 32 intra-hepatic arterioportal malformations and 4 extra-hepatic fistulae. The intra-hepatic arterioportal malformations were classified as right divisional (11/32) and left divisional (21/32) and the left divisional were sub-classified as left medial (16/21) and left lateral (4/21). One patient showed multiple intra-hepatic arterioportal communications with concomitant left medial and left lateral conformations. Two patients with intra-hepatic arteriovenous malformation showed concomitant congenital intra-hepatic shunts. The proposed anatomical classification based on CT angiography could allow veterinary radiologists to have a more systematic approach and help improve the radiologist-surgeon communication.