Repetitive Artery-to-Artery Embolism Caused by Dynamic Movement of the Internal Carotid Artery and Mechanical Stimulation by the Hyoid Bone

A 46-year-old woman without cardiovascular risk factors who was taking oral prednisolone for Sjogren syndrome presented with repeated episodes of transient left hemiparesis and left-sided sensory disturbance over a 2-year period despite preventive therapy with antiplatelets and anticoagulants. Infarcts were always identified in the right middle cerebral artery territory on brain magnetic resonance imaging (Figure 1) without any sign of cerebrovascular stenosis or emboligenic sources. She was referred and admitted to our hospital 2 years after the initial onset. Carotid magnetic resonance angiography showed that the origin of the right internal carotid artery (ICA) bent inward (Figure 2A). However, follow-up magnetic resonance angiography the next day revealed that the origin of the right ICA bent outward, as commonly seen (Figure 2B). On carotid ultrasonography, …