Using Spectral (Pulsed)-Wave Doppler
NOTE: Pulsed-Wave Doppler is available in the Vascular: Access, Vascular: Carotid presets to Pro, Pro Team, and Enterprise customers using either iQ or iQ+ in the United States and iQ+ users in Canada. Pulsed Wave Doppler is also available in the Abdomen, Abdomen Deep, Cardiac, Cardiac Deep, and Cardiac Coherence presets to iQ+ users in the United States.
Spectral Pulsed-Wave Doppler is a quantitative mode that graphically displays blood flow velocity measurements over time. When using Pulsed Doppler, you can:
- View and adjust the position of the sample volume by holding and dragging the gate.
- View and adjust the angle correction by holding and dragging the white caliper dot.
- Switch between live Pulsed Doppler mode and live B-mode by touching the Start Spectrum/Update B-mode button.
- Adjust the gain of the spectral trace by dragging your finger left and right on the trace while the trace is live.
- Adjust the Scale to optimize for high or low flow by touching the Low Flow/High Flow control in the middle of the screen. Note that the control defines your current state.
- Adjust the Scroll Speed of the Spectral Doppler trace by touching the Slow Scroll/Fast Scroll control in the middle of the screen. Note that the control defines your current state.
In order to adjust the Gain and Depth of the B-mode reference image, exit Pulsed Doppler mode and optimize the image in B-mode.
To use Spectral (Pulsed)-Wave Doppler:
- Select the Abdomen, Abdomen Deep, Vascular: Access, or Vascular: Carotid preset.
- Select the Actions button at the bottom of the screen. Select Pulsed Doppler.
- Hold and drag the sample volume gate (the square region in the center of the arrow) to the desired location within the vessel of interest.
- Once positioned, align the direction of the arrow along the direction of flow. If the flow in the vessel is cranial, point the arrow cranially. If the flow in the vessel is caudal, point the arrow caudally.
- Caution: Flow directionality is represented relative to the direction of the arrow. Misalignment of the arrow may lead to misinterpretation of flow direction. Carefully check that the arrow is aligned with the expected blood flow direction.
- Note: Flow in the direction of the arrow will always be depicted above the baseline. Flow against the direction of the arrow will always be depicted below the baseline.
- Hold and drag the arrow, which will automatically pause the spectrum and restart the B-mode reference image.
- Tap the Update B-mode button to manually pause the spectrum and restart B-mode.
- Note: Annotations and measurements may only be added to the Spectral trace region.
Using Spectral Pulsed-Wave Doppler in the Cardiac presets:
For Cardiac presets the pulsed wave doppler mode has the following differences geared towards Cardiac applications:
- There is no angle correction.
- There is no inversion.
- Similar to Fetal Heart Sounds in our OB ⅔ preset, to move the Sample Volume, the user can hold and drag the blue dot to the region of interest. Note: holding in the general vicinity of the blue dot will move the gate as well.
- Because the measurements on the Spectrum could be used for any of the peaks, the velocities are generic: v1 and v2.
- Following the convention used in Cardiac Pulsed Wave Doppler, only the absolute value of the measured velocities is shown.