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

Purpose: To determine the prevalence of different extracranial internal carotid artery (EICA) variations in CT angiography (CTA) of the neck and its predisposing factors.

Methods: In this retrospective study from 2021 to 2023 conducted in the radiology department of Shafa Hospital, Kerman, Iran, all patients who had undergone neck CTA were included. 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 and the apex of the epiglottis and the C2 lower margin.

Results: Of the 106 patients, the mean age was 55.9 ± 16.9 years. 64.2% were men, and 35.8% were women. Considering each patient's bilateral anatomy, the reported 70.28% (149/212) frequency of EICA variations of all arteries. Tortuosity, kinking, and coiling variation were found in 61.8%, 4.2%, and 4.2% of arteries, respectively. Also, 54.72%, 1.89%, and 0.94% of the participants had bilateral tortuosity, kinking, and coiling, respectively. There was a significant relationship between the prevalence of EICA variations and female sex, age, and hypertension.

Conclusion: The frequency of EICA variations in arteries and patients was 70.28% and 73.58%, respectively. Tortuosity was the most common variation. Female sex, old age, and hypertension were significant risk factors for EICA variations.