White matter hyperintensities in migraine are not mediated by a dysfunction of the glymphatic system-A diffusion tensor imaging magnetic resonance imaging study

Objective: We assessed whether brain magnetic resonance imaging (MRI) markers of glymphatic function are altered in patients with migraine and brain white matter hyperintensities (WMHs).Background: The glymphatic system is responsible for the outflow of waste products from the brain. An impaired glymphatic system has been associated with WMH; however, this impairment has not been shown in patients with migraine. Methods: The present cross-sectional study included consecutive patients with migraine from a single tertiary headache center. Glymphatic function was assessed by measuring the diffusion tensor imaging along the perivascular space (DTI-ALPS) technique, resulting in an index value. WMHs were assessed and quantified by using the Scheltens semi-quantitative score.Results: We included 147 patients (120 women [81.6%]) with a median (interquartile range [IQR]) age of 45 (36-50) years. In all, 74 (50.3%) patients had WMHs. The median (IQR) ALPS index was similar in patients with WMHs compared with those without, at 2.658 (2.332-3.199) versus 2.563 (2.222-3.050) (p = 0.344). The Scheltens score did not correlate with ALPS index (rho = 0.112, p = 0.268).Conclusions: Our results suggest that the presence of WMHs is not associated with an impairment in the glymphatic system in patients with migraine. Although negative and worthy of further confirmation, our finding has implications for the understanding of the nature of WMH in patients with migraine.