The role of continuous wave Doppler imaging in a vascular unit

A continuous wave (CW) Doppler imaging system has been used in the assessment of patients with suspected carotid artery disease. In 137 comparisons with conventional angiography the sensitivity of CW Doppler Imaging was 91% and specificity 93% respectively in the detection of greater than 50% diameter internal carotid stenosis. The main diagnostic criterion for greater than 50% internal carotid stenosis was the presence of a peak internal carotid systolic Doppler shift frequency greater than 4 KHz. An examination protocol is recommended which combines CW Doppler imaging with common carotid waveform changes and the temporal artery compression test.