Viewing vertebral arteries by duplex scan: what to expect

In vertebral arteries (v.a) most stenoses occur at their origins. Ultrasound studies with a 7,5 MHz sector duplex-probe are able to reveal the origins in 63— 68% of the right, in 43—62% of the left vertebral arteries (men< omen), whereas the prevertebral and the intertrans versal parts C_5/6—C_3/4 are visualized in 70—90%. The mean cumulative lumen of both v.a. increases by age from 6,0 mm (age<30) to 7,9 mm (age>80) with a clear predominance of the left v.a. in 33%, of the right v.a. in 17%. Hypoplasia of one or both v.a. is present in 5,2%. In a sample of 1131 patients pathological findings occuredin 11% of the vertebral arteries (stenoses or occlusions, steal phenomena) and in 16% of the carotid arteries (stenoses 50% occlusions). In 42% of the cases with infarctions in the vertebro-basilar-supplied territories pathological duplex-findings were present, similary in 20% of infarctions in the carotid supplied territories, and in 15% of vertigo, but also in 62% of patients with peripheral vascular disease without, neurological signs or symptoms — versus only in 3% of control-patients of similar age with out neurological or peripheral vascular disease.