Editors' Note: The Index Vein Pointing to the Origin of the Migraine Aura Symptom: A Case Series

Abstract

Dr. Slavova et al. presented a case series of 6 patients with acute migraine aura who had a prominent draining sulcal vein on emergency MRI susceptibility-weighted imaging (SWI) initially performed for suspected stroke. The vein pointed toward the cortical area that correlated with the clinical presentation. In response, Drs. Bugnicourt and Godefroy raise several concerns regarding the “index vein” finding reported by the authors, including the fact that only 1 patient had demonstrated reversibility of the SWI abnormality, adding to 3 previous case reports that demonstrated reversible venous dilatation in migraine aura; the inclusion of only 6 patients over 7 years, raising questions about the frequency of this finding; the absence of 3D time-of-flight magnetic resonance angiography (MRA) findings in the results; and uncertainty about the underlying mechanism of this finding. Responding to these comments, the authors agree that there are enduring questions regarding the mechanism, reversibility, and potentially low prevalence of the index vein finding, but note that their intention was to introduce this phenomenon and propose a definition that could then be used in future studies to evaluate its diagnostic accuracy for migraine aura. They report that time-of-flight MRA was normal in all reported patients. In summary, the appearance of a prominent vein potentially associated with a culprit cortical area in patients with migraine aura is a phenomenon that requires validation in larger studies of consecutive patients. Dr. Slavova et al. presented a case series of 6 patients with acute migraine aura who had a prominent draining sulcal vein on emergency MRI susceptibility-weighted imaging (SWI) initially performed for suspected stroke. The vein pointed toward the cortical area that correlated with the clinical presentation. In response, Drs. Bugnicourt and Godefroy raise several concerns regarding the “index vein” finding reported by the authors, including the fact that only 1 patient had demonstrated reversibility of the SWI abnormality, adding to 3 previous case reports that demonstrated reversible venous dilatation in migraine aura; the inclusion of only 6 patients over 7 years, raising questions about the frequency of this finding; the absence of 3D time-of-flight magnetic resonance angiography (MRA) findings in the results; and uncertainty about the underlying mechanism of this finding. Responding to these comments, the authors agree that there are enduring questions regarding the mechanism, reversibility, and potentially low prevalence of the index vein finding, but note that their intention was to introduce this phenomenon and propose a definition that could then be used in future studies to evaluate its diagnostic accuracy for migraine aura. They report that time-of-flight MRA was normal in all reported patients. In summary, the appearance of a prominent vein potentially associated with a culprit cortical area in patients with migraine aura is a phenomenon that requires validation in larger studies of consecutive patients.