DUPLEX CAROTID SONOGRAPHY - PEAK SYSTOLIC VELOCITY IN QUANTIFYING INTERNAL CAROTID-ARTERY STENOSIS

Duplex ultrasonography combining high-resolution imaging and Doppler spectrum analysis was performed in 92 consecutive patients (total, 180 vessels) and compared with the findings of conventional arteriography. All duplex studies were categorized into four groups based upon the maximum internal carotid artery (ICA) velocity: group 1: <125 cm/sec; group 2: 125 to 224 cm/sec; group 3: >225 cm/sec; and group 4: no flow. Sensitivities and specificities were highest when peak ICA velocity was used as one of several criteria in quantifying the degree of ICA stenosis. These additional criteria were: (1) the presence of extensive sonographically visible plaque within the ICA; (2) an abnormal spectral waveform with elevated diastolic velocity (>100 cm/sec); (3) resistive pattern (''externalization'') of the common carotid artery (CCA) waveform; and (4) the ratio of the right CCA peak velocity to the left of <0.7 or >1.3. The overall accuracy for the combined groups using all criteria was 94%.