Operation of the Ultrasound Machine

Question 1

What are the following measurement abbreviations commonly used in cardiac M-Mode?

• LA
• LVOT
• Ao
• IVS
• LVEDD
• PW
• LVESD

Answer 1

• LA - Left Atrium
• LVOT - Left Ventricular Outflow Tract
• Ao - Aorta
• IVS - Interventricular Septum
• LVEDD - Left Ventricular End Diastolic Dimension
• PW - Posterior Wall
• LVESD - Left Ventricular End Systolic Dimension

Question 2

What are the following measurement abbreviations commonly used in cardiac Doppler?

• DT
• E
• A
• A dur
• PHT

Answer 2

• DT - Deceleration Time
• E - E-wave peak velocity
• A - A-wave peak velocity
• A dur - A wave duration
• PHT - Pressure half time

Question 3

What physiological monitors may be used in conjunction with an ultrasound?

Answer 3

ECG and respirometer.

The ECG is especially essential as it assists with timing of the cardiac cycle especially during doppler examination.

Question 4

How should colour doppler gain be adjusted?

Answer 4

Increase the colour gain until colour flow is seen as speckling, and then decrease it until the speckling just disappears.

Question 5

What does the smoothing control change for colour flow Doppler?

Answer 5

Smoothing adjusts the amount of colour scan-line averaging, affecting the smoothness and sensitivity of the colour display.

Question 6

What does persist do?

Answer 6

Persist averages data from consecutive frames of the same angle, giving a smoother appearance. If the subject is moving this setting can reduce resolution and may need to be reduced.

Persist can be used on 2D and colour doppler.

Question 7

What does spectral invert change?

Answer 7

This controls whether velocities moving towards the transducer are displayed above or below the zero baseline.

Left: Blood flow towards the transducer is displayed above the baseline (Standard) Right: Blood flow towards the transducer is displayed below the baseline (Inverted)

Question 8

What does the scale setting on colour doppler control?

Answer 8

This control changes the range of colour flow velocities.
Decreasing the scale helps visualise blood flow in low-flow areas.
Decreased scale also reduces the aliasing velocity and will increase the appearance of abnormal flow jets.

Question 9

What does changing doppler gain do?

Answer 9

It adjusts the amplitude of received doppler signals and noise having the same effect as 2D gain.
Too low and the signal is unreadable. Too high and it will be too fuzzy and also unreadable.

Question 10

What does the scale setting on doppler control?

Answer 10

Scale adjusts the range of doppler velocities displayed.

It should be set at the level where the largest complete doppler profile can be displayed on the screen but still mostly fills the screen.
Setting it too high can make the doppler profiles too small for accurate measurement.

Question 11

What does the doppler filter control manage?

Answer 11

Doppler filter removes audible signals of frequencies below the specified Hz level.

It should be set at a level where significant low-flow velocities are still presented, but not so low that “noise” from slow moving tissues are visible around the baseline.

Question 12

What does the sweep speed control on doppler display?

Answer 12

Lower sweep speed displays more cardiac cycles (useful for assessing respiratory variation).
Higher sweep speed displays fewer cardiac cycles but the Doppler waveform appears wider (allows for a more accurate trace).