SPI Exam Flash Cards Set #4

Question 1

To preserve gray scale texture, digital sampling for gray scale images must be at intervals of

Answer 1

one wavelength or less

Question 2

A technique that uses an ensemble of pulses to improve penetration and contrast resolution

Answer 2

coded excitation

Question 3

What units are used for an ultrasound attenuation coefficient

Answer 3

dB/cm/MHz

Question 4

What will increase the dead zone length

Answer 4

increased spatial pulse length

Question 5

What materials are not used to make acoustic lenses

Answer 5

ethylene oxide

Question 6

Power doppler imaging is a good choice when you

Answer 6

want to show tissue perfusion

Question 7

Increasing axial resolution increasing frequency also results in

Answer 7

decreased penetration

Question 8

Each binary digit can represent how many different digital memory states

Answer 8

2

Question 9

Gray scale tissue texture in a color flow imaging system depends on

Answer 9

the product of transmit and receive focusing

Question 10

The strength of the echo in b mode ultrasound is displayed as

Answer 10

pixel brightness

Question 11

What disclosure cannot be made without an authorization signed by the patient

Answer 11

request for medical records after drug treatment

Question 12

A 10dB difference in signal intensity is equivalent to what

Answer 12

ten fold

Question 13

What is a system performance parameter that is assessed using a multipurpose phantom determine the minimum echo amplitude that can be detected

Answer 13

sensitivity

Question 14

Implementation of apodization diagnostic ultrasound systems requires

Answer 14

different voltages to be applied to each element

Question 15

The doppler effect occurs

Answer 15

to all waves coming from a moving wave source

Question 16

You are performing a doppler interrogation of the carotid artery of a patient with a history of CVA. At what doppler angle is the velocity estimate most accurate

Answer 16

zero degrees

Question 17

The rate of sound attenuation is lowest in

Answer 17

water

Question 18

Increasing the PRP

Answer 18

increases maximum depth that can be imaged

Question 19

In a real time scanner, what choice determines the maximum frame rate

Answer 19

depth of view

Question 20

Adjusting the overall gain will increase or decrease the brightness of the image due to what

Answer 20

amplification of the receiver voltage

Question 21

What is the average velocity of ultrasonic waves in soft tissue

Answer 21

1540 m/s

Question 22

The spatial pulse length

Answer 22

usually decreases with higher frequency

Question 23

A beam intensity profile is often mapped with

Answer 23

hydrophone

Question 24

The general range of intensities in diagnostic ultrasound is

Answer 24

0.002 W/cm^2-0.5 W/cm^2SPTA

Question 25

A damaged active element in a mechanical transducer may result in

Answer 25

loss of an entire image

Question 26

A reflected echo is received 39ms after transmission, what is the depth of the interface

Answer 26

3cm

Question 27

Power doppler imaging is so named because

Answer 27

it encodes the power spectrum of the doppler signal into color

Question 28

Lateral resolution is

Answer 28

affected by beam diameter, aperature size and acoustic lens / improved at the focal zone and with increased frequency

Question 29

The function of the damping material in the transducer housing is to

Answer 29

reduce pulse duration, improve axial resolution, improve spatial pulse length

Question 30

Which two scan parameters may be used to indicate the potential for biological effects

Answer 30

thermal index and mechanical index

Question 31

As frequency increases, the penetration will

Answer 31

decrease

Question 32

An ultrasound pulse was transmitted from the transducer and strikes an interface and returns to the transducer. The transmitted and return time was 39 microseconds. What is the total distance traveled

Answer 32

6cm

Question 33

The method for sterilizing transducers is

Answer 33

recommended by the transducer manufacturer

Question 34

The piezoelectric effect is the

Answer 34

the development of an electrical charge across the crystal thickness following deformation

Question 35

While imaging a cyst, you notice shadowing posterior to each lateral border of the cyst. What is the source of the shadow

Answer 35

bending of the sound beam due to different media propagation speeds

Question 36

A method used to improve frame rates with multizone electronic focusing is termed

Answer 36

parallel processing

Question 37

Increasing the PRP

Answer 37

increases the maximum depth that can be imaged

Question 38

The propogation speed for sound is lowest in what biological tissue

Answer 38

fat

Question 39

A technique in which scan lines are directed in multiple directions and then combined together to create one image is called

Answer 39

spatial compounding

Question 40

What would normally have the lowest viscosity

Answer 40

water