[Positron emission tomographic studies of migraine].

Due to technical constraints and randomness of migraine attacks, studies using PET are scarce. Nevertheless, these studies have given new insights into migraine pathogenesis. One of the main facts revealed by PET studies is that posterior cerebral hypoperfusion accompanying migraine auras could also be present in migraine attacks without aura. This hypoperfusion is probably due to an increase of intrinsic vasoconstrictive tone in the cerebral circulation. Using PET within 6 hours after the onset of a spontaneous migraine attack, significant activations of brainstem (midbrain and pons) and of hypothalamus, persisting after headache relief by sumatriptan have been shown. These structures could play the role of migraine attack generators, modulating intrinsic vascular tone and central pain transmission.