Susceptibility Weighted Imaging as a Biomarker for Cortical Spreading Depression

Introduction: Cortical spreading depression (CSD) is thought to be the pathophysiologic correlate of migraine aura. In experimental animals, CSD was shown to cause an increase in oxyhemoglobin. Susceptibility weighted imaging (SWI) on magnetic resonance imaging (MRI) depicts cerebral veins according to their concentration in oxyhemoglobin. The aim of this study was to assess whether the distribution of SWI changes in people with migraine aura resembles the clinical presentation, with a focus on topology. Methods: In this retrospective single-center study, patients were included if they (i) had acute focal neurological symptoms beginning with visual symptoms, (ii) underwent head MRI including SWI within eight hours of symptom onset, (iii) SWI showed focal dilated veins, and (iv) they had a discharge diagnosis of migraine with aura. Eleven predefined cerebral regions of interest (ROIs) were assessed for prominent focal veins (PFVs) on SWI. We determined whether symptoms correlated with the topography of ROIs with PFVs. Results: We found a posterior to anterior gradient of SWI changes during acute migraine aura when visual symptoms were present. Conclusion: MRI with SWI might be able to detect traces of CSD. The posterior to anterior distribution of areas with SWI changes corresponds anatomically to the canonical succession of symptoms in migraine aura.