Transcranial Doppler evaluation of common and classic migraine. Part I. Ultrasonic features during the headache-free period.

To study vascular abnormalities in migraine, transcranial Doppler (TCD) was used for evaluation of 100 consecutive patients with either common or classic migraine during the headache-free period. We insonated the basal cerebral arteries and the internal carotid artery (ICA) in the neck. Particular ultrasonic features in migraineurs included intracranial elevations of mean flow velocity (MFV) above 3 standard deviations of normal values in 16%, probably reflecting increased vasotonus. Marked asymmetry of MFV in corresponding intracranial arteries was found in 12%, and could represent "asymmetrical" vascular tone. Characteristic vascular bruits of low frequency and sometimes harmonic quality were detected in 56%. When compared to TCD findings in 40 young controls, MFV were significantly higher in all intracranial arteries in migraineurs, but not in the cervical ICA. Marked differences were also found for incidence of MFV elevations and vascular bruits (p less than 0.0001). Vascular reactivity in response to eye closing as measured by flow changes in the posterior cerebral artery (visually evoked flow) was significantly greater in migraineurs than in controls (%MFV change, 14.1 +/- 5.4 vs 11.4 +/- 4.8; p = 0.004). TCD features did not discriminate common from classic migraine. Taken together, our results support the view of intracranial vascular abnormality in migraineurs reflecting, in particular, a narrower and more reactive arterial tree. The value of TCD in the differential diagnosis of "vascular headache" and in the study of migraine pathophysiology will have to be determined in the future.