The "index vein" as a sign for migraine aura in the emergency setting.

Background and objectives To assess the usefulness of the "index vein" for making the diagnosis of migraine aura.Methods 400 patients were included when they: i) presented with an acute neurological deficit, ii) had a brain MRI, and iii) had a discharge diagnosis of migraine aura, ischemic stroke, epileptic seizure or controls (n = 100 per group).Results Compared to stroke (2%), epileptic seizure (4%) and controls (1%), the index vein is more prevalent in migraine aura (17%, p < 0.001). The index vein is highly specific for migraine aura (specificity 97%, 95% CI 95-99). The index vein has a positive predictive value for the diagnosis of migraine aura of 70% (95%CI 48-87). The index vein-score has the ability to diagnose migraine aura with a sensitivity of 94% (95%CI 87.4-97.8) and specificity of 73.5% (95%CI 66.8-79.5) at a cut-off of 4 points.Discussion The index vein serves as a good biomarker for migraine aura in the emergency setting.