Ultrasound System Controls and Knobology Flashcards

What is the primary purpose of adjusting the focal zone position on an ultrasound system?

Answer: To maximize lateral resolution at a specific depth

The focal zone is positioned at the depth of interest to minimize beam width and maximize lateral resolution at that location.

When multiple focal zones are used, what is the trade-off?

Answer: Improved resolution at multiple depths but reduced frame rate

Each additional focal zone requires an extra transmit pulse, increasing scan time and lowering frame rate in exchange for better lateral resolution at those depths.

The Doppler angle cursor should be aligned parallel to which structure during angle correction?

Answer: The direction of blood flow

The angle correction cursor must be aligned parallel to the direction of blood flow so that the cosine of the angle can accurately correct the measured velocity.

Which mode uses a single, continuous ultrasound beam and is therefore not depth-selective?

Answer: Continuous wave Doppler

Continuous wave (CW) Doppler uses separate dedicated transmit and receive elements operating simultaneously, detecting all Doppler shifts along the beam with no depth discrimination.

What does the baseline control in spectral Doppler do?

Answer: Shifts the zero-velocity line up or down to prevent aliasing

Moving the baseline shifts the zero-velocity reference line, allocating more of the scale to one flow direction and effectively extending the displayable velocity range in that direction.

Increasing sweep speed on the spectral Doppler display primarily affects:

Answer: The temporal display of waveforms (stretches or compresses them horizontally)

Sweep speed controls how fast the spectral waveform scrolls across the display, affecting how spread out or compressed the waveform appears in time.