A 55-year-old man, without medical history, was admitted for acute onset of headache, vertigo, nausea and unsteady gait. Neurological examination demonstrated gait and limb ataxia, lingual dysarthria, leftward horizontal nystagmus, temperature sensory deficits of the right hemiface and contralateral extremities, consistent with a lateral medullary syndrome.
Diffusion-weighted imaging showed acute bilateral cerebellar infarcts in the PICA territory, sparing the medial areas of both cerebellar hemispheres and extending to the right lateral medulla oblongata and the right cerebellar tonsil, the right ventral part of the inferior cerebellar vermis, and the surface of the right biventral lobule of the cerebellum (figure 1A,B).
MR angiography (MRA) and CT angiography (CTA) showed a right PICA arising from an occluded vertebral artery (VA) as a large-calibre initial vessel crossing the midline and then distally drawing a hairpin form (figure 1C–E). Otherwise, the left PICA was aplastic. A left anterior-inferior cerebellar artery (AICA)-PICA…