The role of cerebral hypoperfusion in the posterior circulation has not bee
n clearly established in migraine. The purpose of this study was to determi
ne the role of vertebral artery (VA) hypoplasia in the pathogenesis of migr
aine. We studied the extracranial part of VA in 59 migraine patients (17 wi
th and 42 without aura) using color Doppler. In migraine with aura, 29% of
patients had hypoplastic VA, and in migraine without aura 7%. In migraine w
ith aura, mean diameter of the right VA was 2.7+/-0.7 mm, and of the left 3
.3+/-0.7 mm; in migraine without aura mean diameter was 3.1+/-0.5 mm on the
right, and 3.3+/-0.6 on the left. In migraine with aura, mean systolic blo
od flow velocity was 55+/-16 cm/s on the right, 60+/-17 cm/s on the left, i
n migraine without aura 57+/-18 cm/s on the right, 57+/-18 cm/s on the left
. We observed higher frequency of hypoplastic VA in migraine with aura, sug
gesting that hypoplasia of VA may be an additional factor which can lead to
hypoperfusion in the posterior circulation during the aura phase.