Direct and indirect evaluation of lesions obstructing the carotid bifurcation. A comparison of Doppler spectrum analysis with angiography.

The diagnostic accuracy of real-time continuous wave (c.w.) Doppler spectrum analysis and of indirect periorbital Doppler examination for detecting carotid bifurcation disease was evaluated. The results of non-invasive studies were compared with contrast arteriograms of patients studied for symptomatic cerebrovascular disease (91%) or for asymptomatic bruits (9%). Periorbital examination was insensitive to less than 75% carotid stenoses and sensitivity to severe stenoses or occlusions was respectively 56% and 85% (mean 73%). Mean sensitivity of real-time C.W. Doppler spectrum was 93% and sensitivity to stenoses of less than 45% diameter reduction was equal to 76%, while specificity in identifying normal carotid arteries was 89% for an accuracy of the method of 91%. Positive and negative predicting values were respectively 89% and 93%. Direct Doppler interrogation of the carotid arteries with real-time C.W. Doppler spectrum analysis was able to distinguish operable stenoses from inoperable occlusions in 87% of the cases.