Anatomical variations of the extracranial internal carotid artery: prevalence, risk factors, and imaging insights from CT-angiography

Abstract Purpose To determine the prevalence of different EICA variations in CT angiography (CTA) of the neck and its predisposing factors. Methods In this prospective study from 2021 to 2023 that was conducted in the radiology department of Shafa Hospital, Kerman, Iran, all patients who had undergone neck CTA were invited to participate in the study. Expert radiologists blindly examined each CTA image for the following: EICA variations—coiling, kinking, straight morphology, and tortuosity—and the distance between the internal carotid artery with the apex of the epiglottis and the C2 lower margin. Results Of the 106 patients, the mean age of the participants was 55.9 ± 16.9 years. 64.2% of the participants were men, and 35.8% were women. The frequency of EICA variations was equal to 70.27%. Tortuosity, kinking, and coiling variation were found in 61.79%, 4.24%, and 4.24% of arteries, respectively. Also, 54.7%, 1.8%, and 0.94% of the participants had bilateral tortuosity, kinking, and coiling separately. There was a significant relationship between the prevalence of EICA variations and female, age, and hypertension. Conclusion The frequency of EICA variations in arteries and patients was equal to 70.27% and 73.5%, respectively. Tortuosity variation was present in 131 (61.7%) arteries, which was the most common variation. Females, old age, and hypertension were risk factors for EICA variations. There was no significant relationship between diabetes, tinnitus, ICA to the apex of the epiglottis, and ICA to the C2 Lower Margin distance with the occurrence of EICA variations.