Anatomical variations of cervical segment of internal carotid artery in patients with subarachnoid hemorrhage

The cervical segment of an internal carotid artery (cICA) usually has a straight vertical course without any branching. In the present study, variations of the cICA were evaluated based on the three-dimensional volume-rendered neurovascular images. The computed tomography angiography images of 56 patients diagnosed with subarachnoid hemorrhage (SAH) were evaluated retrospectively. Two separate researchers, blinded to each other and clinical information of the patients, evaluated the courses of cICA bilaterally. The variations were classified as tortuosity, kinking, and coiling. A total of 112 cICA segments of 56 patients were evaluated. The cICA variations were present in 21.4% of patients and 17.9% of segments. There was tortuosity in 5 (8.9%) patients, kinking in 4 (7.1%) patients, and coiling in 6 (10.7%) patients. Of 41 patients with aneurysmal SAH, there were a cICA variation in 8 (19.5%) patients. A cICA variation was detected in 4 (26.7%) of 15 patients with idiopathic SAH. The cICA variation ratio in SAH patients was concordant with studies performed in different patient groups. Although the ratio was slightly higher in idiopathic SAH patients, there was no statistical significance between the aneurysmal and idiopathic SAH groups. The coiling was more frequent in SAH patients compared to previous studies. The cICA variations tend to be bilateral in SAH patients.