A comparison of angiography, intravenous digital subtraction angiography and duplex ultrasound in the diagnosis of carotid artery atherosclerosis.

Duplex ultrasonography and intravenous digital subtraction angiography (IV-DSA) were used as the initial diagnostic studies in 124 patients referred for evaluation of neurological disorders possibly related to carotid bifurcation disease in the neck. Conventional angiograms were subsequently performed in 29 patients. Diagnostic images were obtained in 100% of the angiograms, 94% of the duplex ultrasonograms and 89% of the IV-DSA studies. Using the angiogram as the reference standard for plaque detection, duplex ultrasonography had a sensitivity of 0.93 and specificity of 0.83. Doppler velocity ratio alone was used to detect all patients with angiographically demonstrated disease but demonstrated a specificity of only 0.35. IV-DSA showed a sensitivity of 0.93 and specificity of 0.91. IV-DSA and duplex ultrasonography agreed in the assessment of degree stenosis in over 90% of cases and we conclude that these two modalities have approximately the same sensitivity and specificity for detecting atherosclerotic disease at the carotid bifurcations.