White matter lesions in migraine and right-to-left shunt: a conventional and diffusion MRI study.

Subjects with migraine with aura (MA) have a high prevalence of white matter lesions (WMLs) on magnetic resonance imaging (MRI). Moreover, right-to-left shunt (RILES), mainly due to patent foramen ovale, is frequently associated with MA. The aim of this study was to clarify the relationship between RILES and WML in MA. We enrolled 87 consecutive subjects affected by MA. Patients were screened for migraine characteristics and cerebrovascular risk factors. Transcranial Doppler was used to diagnose RILES and MRI with T2-weighted and diffusion-weighted imaging (DWI) to evaluate presence, number and volume of WMLs. RILES was present in 45% of patients. We did not detect any DWI hyperintense lesion; WMLs were present in 61% of patients on T2-weighted images. Presence of WMLs did not correlate with any migraine clinical feature, whereas the presence, number and volume of WMLs increased with subjects' age. There was no significant difference in the total volume and number of WMLs in the group with and without RILES. In conclusion, RILES does not increase the likelihood of finding WMLs in migraineurs.