Abstract WP069: The degree of the hyoid-thyroid cartilage movement is associated with the progression of carotid atherosclerosis

Introduction: Carotid arterial arteriosclerosis caused by the movement of the hyoid bone and thyroid cartilage（ HTM-ICA ： Hyoid–Thyroid cartilage Motion–Induced Carotid Arteriosclerosis) are recently known. HTM-ICA can lead to ischemic stroke due to vascular dissection or artery-to-artery embolism. However, thyrohyoid cartilage is not usually visible on MRI. Additionally, the thyrohyoid cartilage moves three dimensionally-up and down during swallowing and left and right during neck rotation and encounters the carotid artery, making it difficult to detect their impacts on the carotid artery in conventional imaging. Purpose: We aimed to reveal whether the degree of HTM is associated with carotid atherosclerosis by using Dynamic Computed Tomography Angiography (Dynamic CTA). Materials and Methods: We enrolled 126 vessels from 63 patients admitted to or visiting in our institute who had a history of ischemic stroke or carotid artery plaque and underwent detailed examination. Dynamic CTA was performed while the patient's neck was rotated to the left and right and swallowing to detect contact between the thyrohyoid cartilage and the carotid artery. The 2 images obtained to compared scenes when the carotid artery underwent maximum deformation with the pre-deformation state. The cross-sectional area of the carotid artery from the common carotid artery to the ICA was measured at 1 mm intervals using vascular measurement software, and the mean deformation rate was calculated at each height. Results: The overall mean vascular deformation rate was 26.4 ± 21.4%. There were no significant differences in deformation rates between sex, hypertension, dyslipidemia, or diabetes. In contrast, deformation rates were significantly greater in patients with carotid plaques ≥ 3 mm than those with carotid plaque less than 3 mm (31.9 ± 26.7% vs 21.0 ± 12.7%, p = 0.004), in patients with carotid stenosis progression than those without progression (36.8 ± 33.4% vs 23.2 ± 14.9%, p = 0.002), in patients treated with carotid endarterectomy (CEA) or carotid artery stenting (CAS) than those without CEA/CAS (37.8 ± 37.4% vs 24.8 ± 17.9%, p = 0.027), and in patients with carotid restenosis after surgery than those without restenosis (51.9 ± 47.5% vs 23.2 ± 14.9%, p < 0.001). Conclusion: The degree of carotid artery deformation caused by hyoid–thyroid cartilage movement during neck rotation and swallowing is one of the causes of carotid artery disease progression.