Pulsed ultrasound

Question 1

The rate at which the transducer applies electronic voltage pulses to the transducer is the….

Answer 1

Pulse repetition frequency

Question 2

What is the order in which the following machine components are activated to produce a single frame?

Answer 2

pulser, beam former, receiver, memory, display.

Question 3

What machine function is responsible for reducing the difference between the smallest and largest received signal amplitudes?

Answer 3

Compression

Question 4

If a sonographer decreases the scan line density avaliable, what mathematical algorithm is employed to fill in the empty pixels?

Answer 4

Interpolation

Question 5

What machine control cannot be adjusted by the sonographer?

Answer 5

Echo arrival time

Question 6

The intensity of the transmit pulse can be increased by:

Answer 6

Output power

Question 7

What machine control could you adjust if there is acoustic drop-out in the far-field of the image?

Answer 7

TGC

Question 8

The receiver _________controls the amount of amplification in the receiver.

Answer 8

Gain .

Question 9

Which of the following US machine components is affected when the sonographer adjusts the output power?
-pulser
-memory
-receiver
-beamformer
- scan converter

Answer 9

Pulser. When the sonographer adjusts the output power, it directly influences the pulser, as this adjustment changes the strength of the electrical pulses sent to the transducer

Question 10

You are performing an early pregnancy ultrasound examination. Which machine control most affects a patient’s exposure?

Answer 10

Output power

Question 11

During an abdominal scan , you are having difficulty visualizing deeper structures. To improve the appearances of these tissues, you double the depth/field of view and add a second focal zone. What is the consequence of these changes?

Answer 11

the number of lines in the image must be reduced to maintain the same frame rate

Question 12

The dynamic range of the displayed echoes can be altered by which machine control?

Answer 12

Compression

Question 13

Whilst performing a pelvic ultrasound examination, the sonographer changes transducer frequency from 5MHz to 3MHz. The resulting effect on image quality is:

Answer 13

both a decrease in resolution, and increased ability to “see” structures at depth

Question 14

Frame rate is influenced by all of the following except:
- presence of multiple focal zones
- depth of imaging
- depth of focus
- width of the region of interest

Answer 14

Depth of focus

Question 15

Explain dynamic range

Answer 15

The ratio of the smallest to largest signal that an US system can handle.

Question 16

What does TGC do?

Answer 16

Equalises the difference in echo amplitudes situated at different depths

Question 17

TGC compensates for?

Answer 17

Attenuation.

Question 18

Which of these are a post processing function?
-TGC
-Read zoom
-Write zoom
-Frame rate

Answer 18

Read zoom.

Question 19

Errors in propagation speed will display reflectors

Answer 19

At an improper depth

Question 20

Posterior acoustic enhancement is caused by:

Answer 20

weakly attenuating structures

Question 21

Shadowing and enhancement are the result of what type of artefact?

Answer 21

Attenuation.

Question 22

f the ultrasound beam passes through a fatty tumor within the liver, and we know that the speed of sound in fat is lower than in soft tissue, where will this fatty tumor be placed in the display?

Answer 22

Farther away than it really is

Question 23

Fluid-filled structures are prone to:

Answer 23

Side lobe, grating and reverberation artefacts