After joining the arterial spin-labeling (ASL) research team at Wake Forest, we began to mine our perfusion database. In addition to the global cases of hyperperfusion, we identified several causes of regional hyperperfusion without any other radiographic abnormality on MRI. Occasionally we thought these might be artifacts, but after reviewing the medical history more carefully, many of the cases were scanned to rule out stroke from either hemiplegia or visual deficits. Only after the patients were en route to the MRI suite did they develop the clinical migraine headache, and they happened to be scanned during this headache. The majority of the migraine cases showed no radiographic abnormality, but the regional hyperperfusion was seen in the cortex associated with the aura symptoms. If they had visual aura, then, during the headache, the occipital lobes were hyperperfused. If they had motor deficits, the frontal/parietal lobes were hyperperfused. I think this perfusion finding reveals something interesting about the pathogenesis of migraine from the vascular theory.

Since publishing the paper we have sought to image a patient during the aura phase, operating under the hypothesis that the affected cortex during the aura would be hypoperfused. Luckily, we happened to catch a patient a few years ago who was having aura symptoms without headache, and the suspected hypoperfusion was confirmed with ASL. This case was presented at the recent 2013 Western Neuroradiology Society meeting, by Dr. Cagley from OHSU.

Because ASL is a noncontrast-based perfusion method, it can be repeated many times. This allows for the potential to dynamically monitor cerebral perfusion during a therapeutic intervention. This unique characteristic of

ASL naturally lends itself to imaging a patient with migraine during the headache, treating the migraine with abortive therapy, and then repeating the perfusion imaging to monitor the changes. Recently, a research group published just such a case.

I am not sure that future clinical patients with migraine will want to get into an MRI scanner during their headache to monitor their treatment response to abortive therapy, but for investigators who are studying novel therapeutic agents, there are certainly future applications.

References

1. Kato Y, Araki N, Matsuda H, et al. Arterial spin-labeled MRI study of migraine attacks treated with rizatriptan. J Headache Pain 2010;11:255–58

 

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