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.