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CBF changes during headache-free periods and spontaneous/induced attacks in migraine with and without aura: a TCD and SPECT comparison study.

BACKGROUND
The aim of the present study was to compare cranial arteries blood flow velocity as measured by means of transcranial Doppler sonography (TCD) with mean regional cerebral blood flow (rCBF) as measured by means of single photon emission computed tomography (SPECT) in migraine with and without aura during headache-free periods and spontaneous and/or induced attacks.


METHODS
Regional cerebral blood flow (rCBF) and systematic ultrasonic Doppler flow were studied by Technetium-99m hexamethylpropilaminoxime (99mTc-HM-PAO) single photon emission computed tomography (SPECT) and transcranial Doppler sonography (TCD) respectively in controls (n=14) and in migraine with (n=13) and without aura (n=35) during headache free-intervals and spontaneous/histamine-induced attacks.


RESULTS
In the migraine without aura group, Doppler flow examinations of the common carotid artery, external and internal carotid artery, ophthalmic artery and middle cerebral artery bilaterally did not reveal significant changes as compared with controls. During attacks, TCD examinations showed a moderate, although not statistically significant, reduction of blood flow velocity in the middle cerebral artery and in the internal carotid artery bilaterally as related to the interictal phase, concomitant with an increase of the flow velocity in the ophthalmic and external carotid artery. SPECT of these patients did not show, on the average, rCBF asymmetries during pain-free periods, although positive findings (i.e., focal hypoperfusion) were found in approximately half of the cases. During attacks, 74% of patients displayed a unilateral hypoperfusion, mainly in the occipital region. Low-flow areas were generally but not always consistent with the site of pain. In the migraine with aura group, significant reduction of blood flow velocity in middle cerebral artery was recorded by TCD on the affected side during attacks, as compared with the pain-free side. Hypoperfusion was registered between attacks by SPECT in approximately 2/3 of the patients. During attacks, a marked reduction of rCBF occurred in most patients (85%), mainly in the parieto-occipital region. The posterior rCBF asymmetries revealed at the SPECT and consistent with the general reduction of blood flow velocity documented by TCD may be related to cerebrovascular tone instability.


CONCLUSIONS
Our findings do not support the paradigm that migraine with and without aura are two different entities.