Term
| Name the first five things used to optimize a 2D image: |
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Definition
- Depth
- Focus
- Gain
- Dynamic Range
- TGC's |
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Term
| If the image is too dark, what are you going to adjust first your 2D-DR/Gain or acoustic power? Why? |
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Definition
| You are going to adjust the 2D-DR/gain first, because by adjusting the acoustic power you are increasing the amplification (compressions/rarefactions) that the patient is exposed to, which can have biological effects (tissue's heated). |
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Term
| If the image on the display shows reflectors that are close to the transducer only, but nothing in the deeper regions, you will adjust ______ first, and if the image is still not improved you will (increase or decrease) ______. |
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Definition
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Term
| The image displays bright echoes from both strong and weak reflectors at all depths. You will (increase/decrease) ____. |
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Definition
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Term
| The image only displays reflectors at 4 cm, but does not show any reflectors at the depth of 1-4 cm. You will adjust _____. |
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Definition
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Term
| What are the advantages and disadvantages of multiple focal number? |
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Definition
ADVANTAGES: Great LATA at multiple locations/depths.
DISADVANTAGES: Decreased temporal resolution (FPS) |
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Term
| What controls affect frame rate in a 2D image? |
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Definition
- Depth
- Multi-focusing
- ApliPure (Spatial Compounding)
- Size and shape of the image
- Write Zoom (AKA Write Magnification)
- Line density (Frame rate) |
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Term
- What kind of zoom do you have on your system?
- If you zoom on the live image, what kind of zoom is this?
- Is this a pre or post processing function? |
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Definition
- Both Read and Write Zoom
- Write Zoom
- Pre processing |
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Term
| What four functions besides the magnification allow you to adjust the frozen image? |
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Definition
- Gain
- TGC's
- Dynamic Range
- Color map |
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Term
| What are the benefits of the frame rate function? |
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Definition
- Better LATA by decreasing FR (like with multi focusing)
- Better temporal resolution by increasing FR |
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Term
| What are the benefits of the frequency function? |
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Definition
- Better axial resolution if you INCREASE frequency
- Better PENETRATION if you DECREASE frequency.
LARD = 1/2 SPL = nv/f |
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Term
| How does doppler angle affect velocity measurements? |
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Definition
| An angle of 60 degrees provides us with the most accurate velocity measurement. Anything over 60 degrees the machine causes a bigger % difference, with overestimation from the actual velocity. |
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Term
| How does sample size affect velocity measurements? |
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Definition
| - A bigger sample size will pick up the slower velocities along the walls of the vessel, resulting in increased spectral broadening (window filling). A smaller gate size placed in the middle of the vessel will just pick up the high velocities of the parabolic flow. This results in a clear window. |
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Term
| Explain the components of triphasic flow and what causes them. |
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Definition
1st component: Forward systolic flow
2nd component: Reversal flow
3rd component: Forward diastolic flow |
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Term
| What parameter of the sound pulse does scale alter? |
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Definition
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Term
| What kind of artifact is displayed if scale is too low? |
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Definition
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Term
| What can be done to avoid aliasing (spectral doppler)? |
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Definition
- Increase scale (PRF)
- Decrease the frequency of the transducer
- Decrease depth
- Increase doppler angle (no more than 60 degrees)
- Decrease baseline
- Use CW doppler |
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Term
| Name 5 things you should adjust first when obtaining a spectral waveform. |
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Definition
- Get long axis view of the vessel.
- Properly set the gate: parallel to flow, no more than 60 degrees, no bigger than 2/3 - 3/4 of the vessel diameter.
- Gain
- Scale
- Filter |
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Term
| To adjust the angle so that it is less than or equal to 60 degrees, the technologist can: |
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Definition
- Heel-toe maneuver
- PW steer function
- Angle correct |
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Term
| Increasing the scale, velocity limits (increase/decrease), displayed waveform (increases/decreases). |
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Definition
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Term
| When obtaining a spectral waveform from a straight healthy vessel, spectral broadening is displayed. What can you do to eliminate this artifact? |
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Definition
- Change gate size
- Increase dynamic range
- Increase filter
- Decrease doppler gain
- Align doppler angle parallel to flow
- make sure vessel is fully elongated |
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Term
| No velocities are detectable in a VERY tight stenosis. What can you do to demonstrate flow in the vessel? |
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Definition
- Decrease wall filter
- Decrease dynamic range
- Open up gate size
- Increase doppler gain
- Decrease doppler scale |
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Term
| Imaging a patient with severe tachycardia, one should ______ ___ ____, that will (increase/decrease) the scale along the x-axis. |
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Definition
- Increase the sweep speed
- decrease
Also it decreases number of cardiac cycles shown |
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Term
| Spectrum is cut off (high velocities are not displayed; there is a reversal of flow in their place.) How can you eliminate this artifact? |
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Definition
- Increase scale
- Decrease doppler frequency
- Decrease depth
- Increase doppler angle up to 60 degrees
- Drop the baseline
- Use CW doppler (aliasing is impossible) |
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Term
| Doppler signal is audible, but spectral waveform cannot be seen, (assume PW is on.) What can you do to fix it? |
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Definition
- Increase doppler gain
- increase gamma
- decrease dynamic range |
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Term
| When the HPRF is operational, can the doppler signal be detected from true and/or ambiguous gate? |
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Definition
| - The doppler signal will be heard coming from both. |
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Term
Can Aliasing be heard in the speakers?
Why? |
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Definition
| No, Because aliasing has to do with the scale being set too low and the signal goes straight to the speakers and THEN to the scan converter which will convert the signal to display aliasing. |
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Term
| Does color mode and spectral use the same technology? Explain. |
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Definition
| - No, color mode uses autocorrelation or cross-correlation, because FFT is not fast enough. Spectral uses FFT for the doppler equation. |
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Term
Is angle important for:
cross-correlation technique? (yes/no)
color doppler technique? (yes/no)
What angle if any, is not acceptable?
Explain. |
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Definition
Yes, Yes, 90 degrees.
At an angle of 90 degrees there is zero doppler shift since it is perpendicular to the vessel, an angle of 90 times cos = 0. If you follow the velocity of blood equation, it would be divided by 0, which is 0, resulting in a black color being displayed. |
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Term
| When you are imaging a healthy vessel with blood through it, no color can be seen. What can you do to improve it? |
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Definition
- Lower the scale
- Steer the color box in the direction of the vessel
- Decrease the filter
- Increase acoustic power
- Increase data number/packet size
- Increase color gain
- Decrease the color frequency |
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Term
| Color doesn't fill the entire vessel. What can you do to improve the color filling? |
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Definition
- Decrease wall filter
- Decrease scale
- Increase acoustic power
- Increase data number/packet size
- Increase color gain
- Increase time smooth
- Increase persistence |
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Term
| Color display shows aliasing. How can you eliminate this artifact? |
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Definition
- Increase the scale
- Adjust color map baseline
- Increase angle up to 60 degrees
- decrease depth
- decrease frequency |
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Term
| The frame rate is too slow, what can you do to adjust it? (color mode) |
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Definition
- Decrease packet size/ data number
- Increase frame rate
- decrease box side/width
- decrease depth |
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Term
| Color image is noisy. What can you do to fix it? |
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Definition
- Increase color filter
- Decrease color gain
- Increase scale
- Increase CDI time smoothing
- Increase frame interpolate |
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Term
| What are 5 things you should adjust first in color mode? |
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Definition
1. Good image of the vessel
2. Steer the box
3. Gain
4. Scale
5. Filter |
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