Vertebral arteries and neck rotation: Doppler velocimeter and duplex results compared

The purpose of this study was to test the validity of Doppler ultrasound (US) velocimeter examination of vertebral arteries during contralateral (to the opposite side) cervical rotation. Vertebral arteries from 20 subjects were insonated using a bidirectional Doppler velocimeter at the suboccipital portal (standard technique) and C2 transverse process level (new technique) during contralateral cervical rotation. The results, regarding persistence or major reduction in Doppler signals, were then compared with those from a colour-flow duplex US scanner using the same procedure. There was complete agreement between the combined suboccipital and C2 velocimeter results and those from the duplex scanner (k = 1.00 at p = 0.01): both sensitivity (n = 5) and specificity (n = 34) were 100%. This study provides evidence to support the validity of bidirectional Doppler velocimeter examination, by an experienced examiner, for the purpose of assessing the effects of contralateral rotation on vertebral artery blood flow.