Evaluation of aortic arch branching pattern variations with computed tomography angiography images

Variations in the branching pattern of the aortic arch are highly diverse and are often encountered incidentally during routine computed tomography angiography scans. This study aimed to determine the prevalence of variations in aortic arch branching patterns in the Turkish population using computed tomography angiography (CTA) images.

CTA images of 1000 patients (500 males, 500 females) who presented to the radiology clinic for various indications between May 2018 and June 2024 were evaluated. The branching variations of the aortic arch were classified into seven main types. The relationship between aortic arch branching pattern variations and sex was assessed using the Chi-square test.

A normal branching pattern (Type 1) was observed in 853 of the 1000 cases, while variations were found in 147 cases. The most common variation was Type 2, in which the brachiocephalic trunk and the left common carotid artery originate from a common trunk, observed in 8.3% of cases. This was followed by Type 3 variation, where the left vertebral artery arises directly from the aortic arch, seen in 4.1% of cases. The third most common variation was Type 4, observed in 1.3% of cases, which involves both the Type 2 branching pattern and the left vertebral artery originating directly from the aortic arch. Type 6 variation, defined as an aberrant right subclavian artery, was seen in 0.8% of cases, while Type 7 (mirror image) variation was observed in 0.1%. Type 5 variation was not detected in any case. Apart from these classifications, a variation in which the left inferior thyroid artery originated directly from the aortic arch was detected in one female patient.

There was no statistically significant difference between sexes in the distribution of aortic arch branching pattern variations (p = 0.067). Patients with aortic arch variations are at increased risk of bleeding and ischemia during thoracic surgery. Awareness of aortic arch variations is particularly important in patients scheduled for thoracic surgery or interventional radiological procedures, as it helps reduce potential risks.