[Various ultrasound methods for studying the vertebral artery--a comparative evaluation].

In a prospective study 451 patients were examined with extracranial continuous-wave (CW) Doppler sonography, transcranial Doppler sonography and color coded duplex sonography in order to evaluate the diagnostic accuracy of the three methods for vertebral artery pathology (hypoplasia, proximal and distal stenosis and occlusion). Color duplex sonography was used as the reference method. CW-Doppler sonography (mastoidal slope) had a sensitivity of 100% and a specificity of 27% for the detection of pathological changes in vertebral arteries (VA). For suboccipital transcranial Doppler sonography these values were 38% and 58%. Extracranial Doppler sonography and transcranial Doppler sonography are often unsuitable for differentiating between proximal stenosis and hypoplasia of VA. Transcranial Doppler sonography of the terminal segments of VA resulted in normal flow parameters in 27% of cases with proximal stenosis and in 50% in cases of proximal occlusion. Flow was normal in these particular cases owing to a more distal collateralisation of the VA. The terms "hypoplasia" and "asymmetric" of VA are discussed.