Non-invasive techniques for the recording of vertebral artery flow and their limitations.

TLDR: The authors describe a pulsed-Doppler technique using a single gate which they believed enabled the identification of the vertebral artery with greater certainty than previous techniques, but critical analysis of their results show that this technique is still not satisfactory and that recordings from other arteries are still being made under the impression that the signals are arising from the vertebrae.

Abstract: The vertebral arteries have always been difficult to examine with ultrasonic Doppler systems. While a number of different techniques have been proposed none would seem to be satisfactory and all suffer from difficulty in identifying, with certainty, the signals arising from the vertebral arteries. The exception to this restriction would appear to be the identification of retrograde vertebral artery flow in “steal” syndromes. The authors raise the question however, whether clinical bias may not play a significant part in such successful examinations since “steal” syndromes can be diagnosed by means other than Doppler recording and the results of such investigations are usually known to the operator before the Doppler examination is made. An example where such clinical bias was responsible for a false diagnosis of a “steal” syndrome is given. The authors describe a pulsed-Doppler technique using a single gate which they believed enabled the identification of the vertebral artery with greater certainty than previous techniques. Critical analysis of their results however, show that this technique is still not satisfactory and that recordings from other arteries are still being made under the impression that the signals are arising from the vertebral artery.