Discriminating migraine aura from transient ischemic attack using <scp>MRI</scp> ‐based oxygen metabolism mapping: A preliminary study

BACKGROUND: Migraine aura is a common acute stroke mimic. Distinguishing between migraine aura (MA) and ischemic stroke or transient ischemic attack (TIA) based solely on clinical presentation can be challenging. Magnetic resonance imaging (MRI) using routine protocols may not definitively differentiate MA from TIA. However, recent advances in the post-processing of dynamic susceptibility-weighted (DSC) perfusion MRI now enable an estimation of cerebral oxygen metabolism. This study aimed to investigate the impact of cerebral oxygen metabolism maps on the differential diagnosis between MA and TIA. METHODS: We performed a retrospective, case-control diagnostic accuracy study of patients admitted to the Lyon Stroke Center from the period 2012 to 2024. Patients who underwent an emergency MRI during initial assessment and received a final diagnosis of either MA or TIA were included. RESULTS: This study included 53 patients: 39 with a final diagnosis of MA and 14 with TIA. Patients with MA showed significantly higher oxygen extraction fraction (OEF) values within the regions of clinical interest compared to patients with TIA. Median OEF change was +15% in the MA group versus -8% in the TIA group (p < 0.001). In receiver operating curve analysis, the OEF ratio discriminated MA from TIA with an area under the curve of 0.89 (95% CI, [0.80, 0.98]). After adjustment for the time interval from symptom onset to MRI, OEF remained an independent predictor of migraine aura (odds ratio: 5.43; 95% CI, [1.69, 9.54], p = 0.009). CONCLUSIONS: Our preliminary findings suggest that migraine aura is associated with a focal increase in OEF during the acute phase, which can be captured using routine DSC perfusion MRI. OEF mapping may aid in distinguishing migraine aura from TIA, but further research is needed to confirm its clinical utility.