[Perivascular tissue vibrations: a criterium for high-grade stenoses of the internal carotid artery].

UNLABELLED: Perivascular tissue vibrations, an artefact of the colour Doppler method, are already known to be a sonographic sign of stenosis but have not yet been investigated systematically in the examination of the internal carotid artery. AIM: The present study is intended to assess the value of this artefact in the diagnosis of stenosis of the internal carotid artery.
METHOD: A total of 167 consecutive cases including a stenosis of the internal carotid artery of at least 50% were diagnosed according to the usual haemodynamic criteria using Doppler and duplex sonography and classified into 10% categories. Intermediate groups were formed for findings that could not be assigned unambiguously. By means of suitable apparatus settings each finding was examined to test whether a perivascular colour artefact was detectable.
RESULTS: In the stenosis categories of 50% to 70% no perivascular colour artefact was found, whereas in the stenosis categories of 80% to 90% this was the case in 80% of the findings, and in the intermediate 75% category in 42% of the findings. The perivascular colour artefact was recognizable even under poor sonographic conditions.
CONCLUSION: When a perivascular colour artefact is seen the diagnosis of a high-degree stenosis (or an AV fistula) is certain. The phenomenon is particularly valuable as a supplementary criterion of stenosis in cases of unfavourable sonographic conditions. However, the perivascular colour artefact may only be used to confirm, but never to exclude, a high-degree stenosis.