The purpose of the study is to evaluate the prevalence of white matter lesions in Chinese migraineurs with and without right-to-left shunt. The aim is to study the relationship among right-to-left shunt, migraine and white matter lesions.

This is a prospective multicenter study of Chinese population. Participants (normal individuals without migraine and migraineurs) are included after standardized diagnostic procedures (TCD and migraine diagnosis). For all the participants, brain MRI and c-TCD are required. Up to 10-15 study sites nationwide will be needed to recruit the planned participant population during a 1-year period.

The information of each participants will be registered, including basic facts, the longitudinal headache history, frequency, location, quality, intensity, duration, accompanied symptoms, precipitating and exacerbating factors, with or without aura, and Headache Impact Test-6 (HIT-6) questionnaire.

Inclusion Criteria:

• patients who fulfilled the criteria for migraine according to the International Classification of Headache Disorders III-beta were included.

healthy volunteers without a history of migraine were included as controls.

Exclusion Criteria:

• Subjects were excluded from the study if they had severe arterial stenosis, an insufficient temporal window, inadequate cubital venous access, and/or were unable to perform the Valsalva manoeuvre (VM) because of severe heart or lung disease.

We detect RLS through contrast-enhanced transcranial Doppler (c-TCD). The normal individuals will be selected to group 1, while those who suffer from migraine will be selected to group 2. All the participants are required to take c-TCD and brain MRI.