Chronic migraine does not increase posterior circulation territory (PCT) infarct-like lesions

Two population-based studies have found an increased prevalence of posterior circulation territory (PCT) infarct-like lesions in migraine, which seemed to increase with attack frequency.

To determine whether chronic migraine (CM) patients are at increased risk of PCT infarct-like lesions.

We prospectively obtained brain MRIs from adult women fulfilling CM criteria. To keep radiologists blinded we also obtained brain MRIs in 15 episodic migraine (EM) patients. MRIs were acquired on a 1.5 T unit. Protocol included whole brain weighted images in sagittal T1 (5 mm slices), axial FLAIR T2 (3 mm) and combined proton density and T2 fast spin echo (3 mm). Two independent neuroradiologists carefully analyzed all the images.

One hundred women with CM participated. Their ages ranged from 18 to 68 years (mean 43.7) and the length of CM ranged from 0.5 to 38 years (mean 9.8). Sixty-three patients (63%) had at least one vascular risk factor. Thirty-three met analgesic overuse criteria. Fifty-one had a history of migraine with aura attacks, though aura frequency was below one per month in all patients except one. Eleven were not on preventatives. We found PCT infarct-like lesions in only 6 CM patients aged 42-64 years (mean age 54 years) who had at least two vascular risk factors.

As frequency of PCT infarct-like lesions in our CM patients was in the low range than that found for EM in general population studies, we conclude that frequency of migraine attacks itself is not a factor increasing PCT infarct-like lesion risk.