Multimodal imaging findings during severe attacks of familial hemiplegic migraine type 2.

Background: Familial hemiplegic migraine (FHM) is a rare monogenic form of migraine with aura with three distinct genetic subtypes (FHM1-3). Imaging studies during acute FHM attacks are scarce in the literature. This is particularly true for the FHM2 subtype.

Patients And Methods: In this monocentric study, we retrospectively evaluated imaging data of four different patients with genetically confirmed FHM2. Analysis comprised a total of eight cMRI and two CT perfusion studies, which were obtained during a total of six different attacks.

Results: cMRI investigations at all available time-points were without evidence of cytotoxic edema. The most prominent finding (four attacks in three patients) was swelling and/or cortical hyperintensity of the affected cerebral hemisphere on T2/FLAIR-weighted MRI. Further changes, encountered only in a few patients, included increased perfusion of the affected hemisphere (as assessed by perfusion CT) as well as dilatation of the middle cerebral artery.

Conclusion: Our data from a sizeable cohort of FHM2 patients highlight that swelling / cortical hyperintensity of the clinically affected cerebral hemisphere - which has been previously reported mainly in FHM1 - can be observed also in FHM2. Further, they suggest that these changes, which tend to be present not in the very beginning, but rather later on during attacks, may be a possible correlate of the prolonged attack duration in our patients.