1. Reliability of continuous-wave Doppler probes
James W. Long, Ph.D., Russell Stevens, B.S., Edgar Lichti, Ph.D., Donald Silver, M.D. 
Journal of Vascular Surgery 
Volume 5, Issue 4, Pages (April 1987)
DOI: / (87)
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

2. Fig. 1
Diagram of system used to determine response characteristics of CW Doppler probes in a tissue-simulating environment.
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

3. Fig. 2
Stepwise processing of frequency shift (Fd) data collected while scanning transversely across a tissue-mimicking matrix containing vessel-simulated tubing through which flowed a synthetic blood substitute at a controlled rate. A, Six sets of scan data superimposed; after digital filtering of each scan (B); and after signal averaging of the six scans (C). D, process is repeated at incremental depths of tissue matrix.
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

4. Fig. 3
Doppler probe response profiles. Left, Contour plot of the dimensions of a response beam profile. Each contour line demarcates tenth percentile increments of maximal expected signals. Right, an axonometric, three-dimensional plot relates Fd response to axial (depth) and transverse (width) distance between probe and “vessel” center.
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

5. Fig. 4
Maximum Doppler probe response over “vessel” center at varying depths of tissue matrix. Data are plotted as mean ± standard error for seven 10 MHz probes with rectangular crystals (lower plot), two 5 MHz rectangular crystal probes (upper plot), and three 5 MHz probes with semicircular crystals (middle plot).
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

6. Fig. 5
Response profiles of 10 and 5 MHz probes illustrate effect of depth through tissue matrix and transverse distance from “vessel” center on Doppler response.
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

7. Fig. 6
Effect of piezoelectric crystal orientation on probe response profile. Profile on the left is generated by 5 MHz probe with rectangular crystals whose long axis is perpendicular to the flow path. On the right the crystal long axes are aligned parallel to the flow vector.
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

8. Fig. 7
Effect of piezoelectric configuration on probe response profile. Profile on the left is produced by a probe with rectangular crystals whereas a probe with semicircular crystals was used for the profile on the right.
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions

9. Fig. 8
Frequency shift (Fd) response calculated as percentage of predicted response during scan across a “vessel” with a probe considered unsatisfactory for quantitative use because of irregular signal fluctuations.
Journal of Vascular Surgery 1987 5, DOI: ( / (87) )
Copyright © 1987 Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery Terms and Conditions