[Doppler sonographic diagnosis of basilar stenoses and obliterations].

We have examined 10,162 patients during the past 5 years using directional continuous-wave Doppler sonography of the vertebral arteries. On the basis of 1,989 retrograde brachial angiograms, we have developed sonographic criteria for demonstrating a significant increase in the peripheral resistance of both distal vertebral arteries and/or the basilar artery. All 11 cases of basilar artery stenosis of at least 60% reduction in lumen diameter (as shown by angiography) exhibited an approximately 40% or higher reduction in the sum of the modified Pourcelot indices of both vertebral arteries in comparison with age-matched controls. The 3 stenoses below 60% reduction in lumen diameter were not detected by sonography. Even a good collateral circulation through rete-mirabile anastomoses did not normalize the modified Pourcelot indices. One case of persistent primitive trigeminal artery with thin-calibred vertebral arteries was also detected by sonography. The high percentage of patients with one hypoplastic vertebral artery in the group of basilar artery stenoses indicates an increased risk for atherosclerosis of the basilar and/or the distal vertebral artery in these patients. All 14 angiographically verified occlusions of the basilar artery were detected by sonographic criteria independent of the occlusive localization. Thus, we believe that directional continuous-wave Doppler sonography is a reliable technique for detecting basilar artery stenoses of at least 60% reduction in lumen diameter and basilar artery occlusions.