A 64‑year‑old woman with hypertension and dyslipidemia presented with two brief episodes of right-sided weakness and dysarthria, each lasting approximately 20 min, within the preceding week. She reported having not experienced headaches, recent trauma, or neck manipulation. Her neurological examination upon admission was normal. No carotid bruit was detected. Routine laboratory test results and electrocardiographic findings were unremarkable. Diffusion-weighted brain imaging did not reveal any acute lesions. Carotid ultrasonography was performed to evaluate for possible carotid artery disease. B-mode imaging revealed diffuse atherosclerotic changes in the left common carotid artery bifurcation (Fig. 1A). Color Doppler and spectral analyses demonstrated coiling and tortuosity of the left internal carotid artery (ICA) with antegrade flow (Fig. 1B). No significant hemodynamic stenosis was observed. The right ICA showed mild tortuosity without coiling. These findings were confirmed using magnetic resonance angiography, which excluded carotid artery dissection and high-grade stenosis (Fig. 1C). The patient was managed with antiplatelet therapy, statins, and strict management of vascular risk factors.

ICA tortuosity encompasses several morphological patterns, including vessel elongation, kinking, and coiling. Its development has been linked to inherited predisposition to conditions including fibromuscular dysplasia and atherosclerotic vascular disease.¹ Among the systems for categorizing ICA tortuosity, the Weibel-Fields classification separates lesions into three types. Type 1 describes elongated ICAs that follow smoothly curved C-, U-, or S-shaped courses. Type 2 refers to arteries that form tight loops or coils wound around an axis. Type 3 describes sharply angulated, kinked segments in which the vessel bends into a V configuration.^1,2 Coiling and tortuosity of the extracranial ICA can be detected using noninvasive color Doppler ultrasonography. Careful sonographic assessment with the head straight, then turned to the right or left can reveal change in flow velocity or diameter of the ICA. This information is important for appropriate stroke risk stratification and management.^3,4