Iron in deep brain nuclei in migraine? CAMERA follow-up MRI findings

Introduction In the CAMERA population-based MRI study, migraineurs below the age of 50 had decreased T2-values indicative of increased iron deposition in several deep brain nuclei. Longer migraine history was associated with lower T2-values, suggesting an association between migraine attacks and iron accumulation. In the present nine-year follow-up study of the CAMERA cohort we re-measured the T2-values in deep brain nuclei to assess the evolution over time. Methods Baseline and follow-up T2-values measured in several basal ganglia of 128 participants (38 control, 90 migraine) were analyzed using quantitative T2 measurements and multivariate regression analysis. Results T2-values of most deep brain nuclei were increased - instead of an expected further decrease when only age-related iron accumulation would have played a role - compared to baseline (both among controls and migraineurs) and were not different in either group. In migraineurs, no differences were found by gender, migraine severity or subtype. Conclusion This study did not provide supportive data for migraine related increased iron accumulation in deep brain nuclei, but neither is it able to reject such hypotheses. Increased T2-values probably point at microstructural tissue changes that counteracted earlier accumulated iron effects. We hypothesize that, with aging, migraine-induced iron-related brain changes are obscured by other age-related tissue changes.