MRI spots (white matter lesions) in patients with migraines.

Performing an MRI scan is unnecessary in the vast majority of migraine sufferers. However, many migraineurs end up having this test because they are concerned about having a brain tumor or another serious condition and because many doctors order MRIs to avoid a possible malpractice suit, however remote the possibility. MRI scan does not involve any radiation, so it is not harmful, but it can cause other problems, besides wasting healthcare dollars. The harm often comes from finding an abnormality on the MRI which is benign, but nevertheless can be very anxiety provoking.

Lesions seen on MRI scans which are benign but very upsetting to patients are arachnoid cysts and venous malformations.

The most common finding though is white matter lesions (WMLs), which doctors sometimes jokingly refer to as UBOs – unidentified bright objects. The origin and the meaning of these spots remains unclear, although the most likely explanation is that these spots are due to ischemia or lack of blood flow. A Dutch study of 295 men and women published in 2004 showed that people who have migraine with aura had a higher risk for silent strokes. As far as WMLs, surprisingly, control subjects, that is people without migraines, had the same high chance of having WMLs as those with migraines – about 38%. However, women with migraine were more likely to have these lesions, regardless whether they had auras or not. A follow-up study published in 2012 reported on 203 of the original 295 patients who underwent another MRI scan 9 years later. This study showed that 3 out of 4 women had progression of these lesions, but they did not have any more strokes. They also did not find an increased risk of dementia in these women.

Another important finding from this long-term study is that migraine sufferers who tend to have syncope attacks (fainting) or near-fainting or feeling lightheaded on standing up or when having blood drawn are more likely to have these WMLs. This suggests that lack of blood flow to the brain may be responsible for WMLs. These findings were presented in a separate article in Neurology.

So, while we still don’t know the cause of WMLs they do appear to be benign and do not lead to other serious problems.

If WMLs are related to strokes as suggested by the fact that drop in blood flow to the brain may predispose one to having WMLs and in a severe form drop of blood flow causes strokes, then possibly approaches that prevent strokes may also prevent WMLs. Even if they are benign, having WMLs is concerning because we may not yet know some of their negative consequences. We know that the risk of strokes can be reduced by avoiding smoking, controlling blood pressure in people with hypertension and blood glucose in diabetics, maintaining normal cholesterol levels, maintaining normal weight, and exercising regularly.

A recent study published in Neurology showed that WMLs are strongly correlated with the frequency of exercise – the more people exercised the less likely they were to have WMLs.

Art credit: JulieMauskop.com