No evidence of widespread microstructural white matter changes was found in patients with migraine when compared to controls. However, a gradual process may be responsible for evolution of focal invisible microstructural changes into focal migraine-related white matter hyperintensities (WMH). This according to a recent study that used magnetization transfer imaging to assess white matter tissue integrity in migraine and to examine whether white matter microstructure was more diffusely affected beyond visible WMH. Researchers found:
- 137 patients with migraine and 74 controls were scanned at baseline and at a 9-year follow-up.
- Magnetization transfer ratio (MTR) values for whole brain white matter did not differ between patients with migraine and controls.
- In patients with migraine but not in controls, normal-appearing white matter that later progressed to WMH at follow-up had lower mean MTR at baseline compared to contralateral white matter.
Arkink EB, et al. Microstructural white matter changes preceding white matter hyperintensities in migraine. [Published online ahead of print July 11, 2019]. Neurology. doi: 10.1212/WNL.0000000000007940.
The investigators have been evaluating imaging changes in those with migraine and controls across nine years in a study called the Cerebral Abnormalities in Migraine, an Epidemiological Risk Analysis (CAMERA) study. They, and other investigators, have used a variety of MRI techniques for this study, including diffusion weighted MRI, as well as magnetization transfer imaging (MTI). The lower MTRs at baseline in those with migraine suggest that there are microstructural white matter changes that can be demonstrated prior to visible WMHs. The authors speculate that these changes may be “the presence of focal occult microstructural alterations or damage in brain tissue integrity prior to the appearance of visible deep WMHs on conventional T2-weighted MRI.” The WMHs appear progressive in women with migraine of disease activity. The basis for these microstructural changes is unknown, sometimes they remit, and they do not appear associated with long term cognitive changes in those with migraine. —Stewart J. Tepper, MD, FAHS, Professor of Neurology, Geisel School of Medicine at Dartmouth, Director, Dartmouth Headache Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH