Cerebrovascular reactivity to hypercapnia in patients with migraine: A dual‐echo arterial spin labeling MRI study

Objective This study aimed to compare cerebrovascular reactivity between patients with migraine and controls using state‐of‐the‐art magnetic resonance imaging (MRI) techniques. Background Migraine is associated with an increased risk of cerebrovascular disease, but the underlying mechanisms are still not fully understood. Impaired cerebrovascular reactivity has been proposed as a link. Previous studies have evaluated cerebrovascular reactivity with different methodologies and results are conflicting. Methods In this single‐center, observational, case–control study, we included 31 interictal patients with migraine without aura (aged 19–66 years, 17 females) and 31 controls (aged 22–64 years, 18 females) with no history of vascular disease. Global and regional cerebrovascular reactivities were assessed with a dual‐echo arterial spin labeling (ASL) 3.0 T MRI scan of the brain which measured the change in cerebral blood flow (CBF) and BOLD (blood oxygen level dependent) signal to inhalation of 5% carbon dioxide. Results When comparing patients with migraine to controls, cerebrovascular reactivity values were similar between the groups, including mean gray matter CBF‐based cerebrovascular reactivity (3.2 ± 0.9 vs 3.4 ± 1% ΔCBF/mmHg CO2; p = 0.527), mean gray matter BOLD‐based cerebrovascular reactivity (0.18 ± 0.04 vs 0.18 ± 0.04% ΔBOLD/mmHg CO2; p = 0.587), and mean white matter BOLD‐based cerebrovascular reactivity (0.08 ± 0.03 vs 0.08 ± 0.02% ΔBOLD/mmHg CO2; p = 0.621).There was no association of cerebrovascular reactivity with monthly migraine days or migraine disease duration (all analyses p > 0.05). Conclusion Cerebrovascular reactivity to carbon dioxide seems to be preserved in patients with migraine without aura. Plain Language Summary Patients with migraine have a higher risk of vascular diseases, possibly due to a decreased function of the blood vessels, but past studies have not consistently shown this. We compared the function of blood vessels in the brains of patients with migraine and those without migraine by looking how brain blood flow changed in response to breathing in carbon dioxide. We found no differences in the ways in which blood vessels responded to inhaled carbon dioxide between the groups, which suggests that this aspect of blood vessel function does not differ between patients with and without migraine. [Correction added on 20th March 2024, after first online publication: The “Plain Language Summary” section has been added].