EVALUATION OF THE BASILAR ARTERY FLOW VELOCITY BY TRANSCRANIAL DOPPLER ULTRASONOGRAPHY

Using transcranial Doppler ultrasonography (TCD), we measured flow velocities along the vertebrobasilar axis via the suboccipital window in 99 patients to investigate the hemodynamics of the basilar artery (BA). Nineteen of them had posterior circulation pathology (occlusive lesions of the BA or vertebral arteries), 36 had anterior circulation pathology, 1 had multiple aneurysms and the remaining 43 cases had no lesions. Confirmation was obtained by cerebral angiography in all cases. In the subjects without lesions, the mean BA velocity was 32.8 +/- 12.4 cm/s, and it was almost constant along the vessel. On the other hand, abnormal findings such as no flow signal, constant low velocity flow, retrograde flow, a signal from the anterior spinal artery or an abrupt increment of velocity were noted in most patients with posterior circulation pathology. Constant high velocity was noted in patients with anterior circulation pathology and collateral flow from the posterior circulation. Thus, TCD appears to be useful for assessing BA circulation.