The “fidget spinner” sign in cardioembolic bilateral medial medullary infarction: an imaging clue to proximal anterior spinal artery occlusion

Bilateral medial medullary infarction is a rare and clinically severe form of brainstem stroke. A patient presented with acute neurological deficits, and diffusion-weighted imaging revealed a distinctive pattern resembling a “fidget spinner.” CT angiography demonstrated marked asymmetry of the vertebral arteries, with hypoplasia of the right vertebral artery. A review of 97 previously reported cases confirmed the exceptional rarity of cardioembolic etiology in this condition. In this context, the present case represents an uncommon coexistence of a rare anatomical pattern and a rare vascular mechanism. These findings suggest that infarct morphology on diffusion-weighted imaging may reflect underlying vascular anatomy and the level of arterial involvement in bilateral medial medullary infarction.