Using perfusion weighted imaging, we studied 28 spontaneous migraine episod
es; 7 during visual aura (n=6), 7 during the headache phase following visua
l aura (n=3), and 14 cases of migraine without aura (n = 13). The data were
analyzed using a region-of-interest-based approach. During aura, relative
cerebral blood flow (rCBF) was significantly decreased (27%+/-0.07) in occi
pital cortex contralateral to the affected hemifield. rCBV was decreased (1
5%+/-0.12) and mean transit time increased (32%+/-0.3), persisting up to 2.
5 h into the headache phase. Other brain regions did not show significant p
erfusion changes. During migraine without aura, no significant hemodynamic
changes were observed. In one patient who experienced both migraine with an
d without aura, perfusion deficits were observed only during migraine with
aura. These findings suggest that decremental blood flow changes in occipit
al lobe are most characteristic of migraine with aura.