Bilateral Caudate Nucleus Infarction Associated with a Missing A1 Segment

We describe a case of bilateral caudate nucleus infarction caused by cardioembolic stroke associated with a variant circle of Willis. The patient was an 81-year-old man with atrial fibrillation who presented with a sudden disturbance of consciousness. When he became more alert a few days later, he was abulic with no spontaneous speech or activity. A magnetic resonance imaging scan of the brain revealed cerebral infarction of bilateral caudate nucleus heads and the left frontal lobe. The left A1 segment was absent on 3-dimensional computed tomography angiography. One year later, abulia had completely resolved. Bilateral caudate nucleus infarction with variant circle of Willis is rare.