1. Asymptomatic high-grade internal carotid artery stenosis: Is stratification according to risk factors or duplex spectral analysis possible? 
Gregory L. Moneta, MD, David C. Taylor, MD, R.Eugene Zierler, MD, Andris Kazmers, MD, Kirk Beach, MD, PhD, D.E. Strandness, MD 
Journal of Vascular Surgery 
Volume 10, Issue 5, Pages (November 1989)
DOI: / (89)
Copyright © 1989 Society for Vascular Surgery and the North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

2. Fig. 1
Duplex spectra from a high-grade internal carotid artery lesion. The peak systolic frequency is off the scale, there is marked spectral broadening, and the end-diastolic frequency (EDF) exceeds 4.5 kHz.
Journal of Vascular Surgery  , DOI: ( / (89) )
Copyright © 1989 Society for Vascular Surgery and the North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

3. Fig. 2
End-diastolic frequencies of unstable (group B) high-grade internal carotid artery lesions according to associated type of neurologic event. End-diastolic frequency is not predictive of the specific associated neurologic event.
Journal of Vascular Surgery  , DOI: ( / (89) )
Copyright © 1989 Society for Vascular Surgery and the North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

4. Fig. 3
Distribution of EDFs in groups A and B. Seven out of eight internal carotid arteries that occluded in follow-up were associated with an EDF of >6.0 kHz.
Journal of Vascular Surgery  , DOI: ( / (89) )
Copyright © 1989 Society for Vascular Surgery and the North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

5. Fig. 4
An ROC curve of the sensitivity and specificity of individual EDFs in predicting subsequent neurologic events (transient ischemic attack, stroke or asymptomatic internal carotid occlusion). The EDFs in kHz appear along the course of the curve.
Journal of Vascular Surgery  , DOI: ( / (89) )
Copyright © 1989 Society for Vascular Surgery and the North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

6. Fig. 5
Distribution of end-diastolic frequencies (EDFs) according to angiographic level of stenosis in 22 randomly selected patients with high-grade internal carotid stenosis by duplex scanning and preoperative carotid angiography.
Journal of Vascular Surgery  , DOI: ( / (89) )
Copyright © 1989 Society for Vascular Surgery and the North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions