[Color-coded duplex ultrasound in pre-occlusive stenoses of the internal carotid artery]

In a prospective study the results of 238 consecutive ultrasound examinations of the carotid artery were correlated with angiography to test the reliability of colour coded duplex sonography in preocclusive carotid artery disease. This series was compared with a series of 611 vessels with angiographically controlled conventional duplex sonography. In 61 resp. 84 cases stenoses > or = 90% or occlusions of the internal carotid artery were found. The reliability of colour coded duplex sonography for the diagnosis of > or = 90% stenoses was extremely high (sensitivity and specificity 98%), as well as in preocclusive, > 95% stenoses (100% and 98%), and for the diagnosis of occlusion, after exclusion of angiographic false positive diagnosis of occlusion (95% and 99%). Statistically colour coded flow imaging failed to increase significantly the high diagnostic sensitivity or specificity of conventional duplex sonography, especially in preocclusive carotid artery disease. However, the remarkable increase in frequency of the diagnosis preocclusive stenosis with the introduction of colour coded Duplex Sonography probably reflects a higher sensitivity of this method. In addition the direct comparison of both ultrasound techniques showed a better image of the vessel wall abnormalities and the residual lumen with colour coded duplex sonography.