Posterior circulation stroke: dizziness. Brain MRI: There is a subcentimeter area of restricted diffusion and high T2 signal in the superior cerebellar vermis. The brainstem and supratentorial brain are otherwise unremarkable, aside from minimal nonspecific T2 hyperintensity in the left frontal lobe white matter. There is no evidence of intracranial hemorrhage or mass. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The orbits, skull, and scalp soft tissues are grossly unremarkable. There is mild mucosal thickening in the maxillary sinuses.Brain MRA: There is apparent paucity of flow-related enhancement of the distal portion of the right PICA. The segment of the left vertebral artery distal to the left PICA is markedly diminutive. There is a fetal left PCA. There is an azygous left ACA. The rest of the intracranial arteries are grossly unremarkable and there is no evidence of saccular cerebral aneurysms.Neck MRA: The exam is non-diagnostic due to suboptimal contrast bolus timing.
1. Small acute infarct involving the superior cerebellar vermis.2. Apparent paucity of flow-related enhancement of the distal portion of the right PICA may indicated steno-occlusive disease versus artifact. 3. The segment of the left vertebral artery distal to the left PICA is markedly diminutive, which may be developmental. 4. The neck MRA is non-diagnostic due to suboptimal contrast bolus timing. 