Prevalence of arterial branches arising from the extracranial internal carotid artery on CT angiography

Abstract

Although it is well known that arterial branches may rarely arise from the cervical internal carotid artery (ICA), their incidence has not been adequately evaluated on computed tomography angiography (CTA). We investigate the prevalence of congenital and non-congenital anomalous branches arising from the cervical ICA by a 5 year retrospective review of neck CTAs performed on 2,602 patients. We found a higher frequency of arteries arising from the ICA than suggested by the existing literature, including a 0.49 % prevalence of the occipital artery origin and a 6.25 % prevalence of the superior pharyngeal branch of (the pharyngeal trunk of) the ascending pharyngeal artery. In addition, six cases of recanalized intersegmental arteries providing collateral flow to the cervical ICA from the cervical vertebral artery were identified. This is the first large, retrospective CTA study evaluating the incidence of these anomalous vessel origins.

Common and uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of

“…In our series of patients, we observed this variation in 0.115 % (Fig. 9 ) [in accordance with the current literature finding of 0.08–0.2 %, but lower than in a recently reported study (0.49 %)] [ 19 ].…”

Detection of Anomalous Cervical Internal Carotid Artery Branches by Colour Duplex Ultrasound

“…Thereby it is believed these buds may connect with the ICA and develop into a branch. 24 In a recent study, the most frequently encountered branch is the superior branch of the ascending pharyngeal and has been detected at a rate of 6.24% by Small et al, 16 similar to the 4% prevalence found in this study. It is to be noted that there is a paucity of imaging studies directly searching for anomalous ICA branches.…”

“…It is to be noted that there is a paucity of imaging studies directly searching for anomalous ICA branches. 11,16 Other ECA branch possibilities include, occipital, laryngeal, and sternocleidomastoidal branches. 4,6e8,21e27,31 In early post mortem studies, a detection rate of the ascending pharyngeal artery arising from the ICA was as high as 9% in a series of Japanese subjects in 1928 conducted by Adachi and Hasebe.…”

“…None. Hypoglossal 37,48e50 Proatlantal intersegmental 15,31,39,47,50,51 Vertebral 33,52 Anomalies of external carotid artery branch origins Superior pharyngeal branch of the ascending pharyngeal artery 16 Ascending pharyngeal 5,7,15,16,35,53e56 Sternocleidomastoidal (branch of superior thyroid or occipital artery) 27 Internal maxillary artery 38,56 Superior laryngeal 9 Occipital 6,8, 15,16 Origin of superior thyroid, occipital and ascending pharyngeal from a common trunk 57 Table 3. Potential clinical implications of ICA branches.…”

Subclavian Carotid Bypass of Occluded Common and Internal Carotid Arteries Facilitated by an Anomalous Branch of the Internal Carotid Artery

“…5 A recent study by Small et al demonstrated a 0.49% prevalence of an anomalous occipital artery and a 6.25% prevalence of a superior pharyngeal artery from the ICA, both rates greater than previously seen in the literature. 3 Although rare, anomalous branches of the ICA have significant implications in the surgical treatment of atherosclerotic carotid artery disease because of the natural progression of occlusion to the next branch of the ICA. If an anomalous branch exists, retrograde flow either from this branch to the ICA or vice versa may maintain patency of the distal ICA.…”