Objective To investigate the relationship between different carotid geometry and the formation of atherosclerotic plaque in the initial part of internal carotid artery (ICA) in patients with ischemic stroke based on CT angiography (CTA) of head and neck.

Methods Data of patients hospitalized for ischemic stroke and who completed head and neck CTA were retrospectively collected. Ninety-two patients with atherosclerotic plaques at the beginning of unilateral ICA were included in the plaque group, and 30 patients with bilateral normal ICA with similar demographic variables were selected as the control group. At the same time, unilateral ICA initiation atherosclerotic plaque were divided into plaque side and non-plaque side. The differences of carotid artery geometry between the two groups and in the plaque and non-plaque sides were compared.

Results The geometric parameters of carotid artery, such as internal carotid artery angle, carotid artery dilation and ICA/common carotid artery (CCA) diameter ratio in the plaque group showed significant difference compared with those in the control group (P < 0.05). Compared with the non-plaque side, the internal carotid artery angle on the plaque side was significantly larger, carotid artery dilation was significantly higher, and ICA/CCA diameter ratio was significantly lower (P < 0.05). Multivariate Logistic regression analysis results showed that larger internal carotid artery angle and carotid artery dilatation and lower ICA/CCA diameter ratio were associated with atherosclerotic plaque formation at ICA initiation.

Conclusion The geometric features of carotid artery are different among different individuals. In patients with mild ICA atherosclerotic lesions, larger internal carotid artery angle, carotid artery dilation and smaller ICA/CCA diameter ratio are independent risk factors for atherosclerotic plaque formation at the initiation of ICA.