DIFFERENTIATING SUBTOTAL CAROTID-ARTERY STENOSES FROM OCCLUSIONS BY COLOR-CODED DUPLEX SONOGRAPHY

During a 9-month period the carotid arteries of 2420 consecutive patie nts were investigated by conventional Doppler and duplex ultrasonograp hy as well as by colour-coded duplex sonography. Of 186 internal carot id arteries showing a diameter reduction at the bifurcation level of 9 5% or more by conventional techniques, 131 underwent X-ray angiography which revealed a subtotal stenosis in 25 and an occlusion in 106 case s. Using a total of ten criteria for describing the colour-coded duple x findings, the ''distal colour filling'', a combination of three sing le criteria, could be found in all subtotal stenoses and none of the o cclusions. ''Distal colour filling'' was diagnosed if a colour signal was present for a length of at least 1.5 cm directly behind an assumed stenosis comprising the whole area between the vessel walls. Our resu lts suggest that non-invasive colour-coded duplex sonography is superi or to conventional Doppler and duplex techniques and comparable to inv asive X-ray angiography in differentiating extracranial subtotal carot id artery stenoses from occlusions.