Audible interpretation of carotid Doppler signals. An improved technique to define carotid artery disease
R. W. Barnes, L. Nix and S. E. Rittgers
Direct interrogation of the common, internal, and external carotid arteries
with a bidirectional Doppler detector was performed on 199 vessels in 101
patients. Audible interpretations of normal, disturbed (stenotic), or
absent (occluded) flow signals were made by vascular technologists and the
results were compared with independently assessed carotid arteriograms. The
sensitivity in detecting severe (greater than or equal to 50%) stenosis or
occlusion was 9.2%, with correct differentiation of these two conditions in
84% of vessels. Nonobstructive (less than 50%) stenoses were detected in
30% of cases. The specificity in identifying normal carotid arteries was
91%. The predictive values of normal, abnormal, and absent flow signals
were 95%, 90%, and 90%, respectively. Direct carotid Doppler signal
analysis is more accurate than indirect periorbital Doppler screening in
defining carotid stenosis or occlusion.
