Angiographic Variation of the Internal Carotid Artery and its Branches in Horses

Abstract

Objectives: To record the angiographic anatomy of the equine internal carotid artery (ICA) using angiography techniques. Study design: In vitro descriptive study. Sample Population: Equine cadaver specimens (n=50). Methods: Head and neck specimens from horses of mixed breed, age, sex, and use without a history of guttural pouch disease had carotid and cerebral angiography using conventional (n=7) and rotational angiography (43). Angiographic findings were verified by arterial latex casts. Results: Variation in ICA anatomy was categorized into 4 groups: (1) the internal carotid and occipital arteries arising as a common trunk; (2) an aberrant branch of the extra-cranial ICA connected to the basilar artery; (3) an aberrant branch of the ICA ramifying into the surrounding tissue and not connected to any other vessels; and (4) an aberrant branch of the ICA giving rise to several smaller satellite branches, including connections to the caudal branch of the ipsilateral occipital artery. Conclusion: Rotational angiography is useful for identification of anatomic variation in the ICA that could be important in achieving vascular occlusion in the treatment of guttural pouch mycosis.