Cleveland Family Study

10.12 Spectral Trace Analysis

10.12.1 Spectral Doppler Auto-Trace

Study sites with ultrasound machines that have spectral Doppler auto-trace capability from a live frozen image will use this function for the baseline FMD and NTG spectral waveforms. The baseline portion of the procedure will not be time sensitive.

There will not be adequate time to use this type of Doppler function for the immediate release Doppler during the FMD portion of the procedure.

The spectral Doppler auto-trace analysis function will also be used for the post-NTG spectral waveforms unless too much time and/or too many keystrokes are required to perform the function.

10.12.2 Artery Occlusion

1. The annotation will be changed from “UA BL” to “UA”.
2. The zoom function will be turned off to visualize the full length of the artery.
3. The color flow will be activated and the time will be mentally noted.
4. The occlusion cuff will be slowly inflated to 40 mmHg above the patient’s baseline systolic pressure to obtain occlusion of the brachial artery.
5. The occlusion systolic measurement will be recorded on the data sheet.
6. The cable end of the scanhead will be moved either up or down to keep the brachial artery in view as the cuff is inflated in order to prevent the need to search for the artery during reactive hyperemia. This will cause the immediate release maximum Doppler velocities to be missed.
7. The exact time to the second that color flow is no longer observed in the brachial artery will be recorded on the data sheet.
8. The PW Doppler cursor will be activated. The horizontal position of the PW Doppler cursor will not be changed from its baseline position. Due to the compression of the cuff, the SV depth may need to be adjusted slightly.
9. The PW Doppler triplex image will be activated.
10. The PRF will be increased to 10 kHz to accommodate the increased velocities associated with reactive hyperemia.
    • Increasing the PRF to 10 kHz will typically cause the ultrasound machine to no longer provide simultaneous real-time 2-D images with the real-time spectral trace. To provide such a high PRF, the machine will provide only an updated 2-D image.
11. The spectral trace will be turned off. The SV cursor will remain on the screen. This will allow a real-time 2-D image until the precise moment the high PRF PW Doppler will be needed.
12. The precise moment to deflate the cuff will be calculated by adding 5 minutes to the occlusion time. Then 1 minute will be added to the release time as the goal for obtaining a post-stimulus image. Both of these times will also be recorded on the data sheet.
13. During the 5-minute occlusion period, the duplex (2-D and color flow) image, the patient’s systolic BP, the pressure in the occlusion cuff and the time will be monitored.

• Sufficient pressure will be maintained in the occlusion cuff to totally prevent blood flow for the entire 5-minute period.
• If the pressure falls and color flow is observed in the artery during the 5-minute occlusion period, the cuff will be pumped back up and the 5-minute occlusion period begun again from the time point when flow is re-occluded.
• Maintaining visualization of the artery during this period significantly improves the probability that the appropriate post hyperemia images will be recorded.