all review slide questions

Question 1

Because US pulses are usually 2-3 cycles , axial resolution is usually equal to ______ to ______ wavelengths.

2, 3
4, 6
1, 3.5
1, 1.5

Answer 1

1, 1.5

Question 2

A two-cycle pulse of 5 MHz ultrasound produces separate echoes from reflectors in soft tissue separated longitudinally by 1 mm.

T/F?
Why?

Answer 2

True

axial res 0.3 mm

Question 3

5 MHz unfocused transducer
Element width – 13 mm
Near zone length – 14 cm

Lateral resolution is best at what depth?

Lateral resolution at 14 cm is

Lateral resolution at 28 cm is

Answer 3

14
6.5
13

Question 4

Lateral resolution is improved by:
Damping
Pulsing
Focusing
Matching
Absorbing

Answer 4

focusing

Question 5

An unfocused 3.5 MHz
13 mm wide transducer
n – 3 cycles
AR is this case is better that LR
True or false?

Answer 5

True

Question 6

What Doppler angle yields the greatest Doppler shift? Least Doppler shift?
- 90
-45
0
45
90

Answer 6

greatest = 0

least=90

Question 7

The control that sets the gray-scale brightness below which color will be displayed instead of gray-scale at a pixel location is -
Priority
Line density
Persistence
Ensemble length 
Scale

Answer 7

priority

Question 8

Color Doppler uses autocorrelation technique to yield what four types of information in real time?
Mean
Variance
Power
Sign

Answer 8

mean

Question 9

In color Doppler instruments, color is used only to represent flow direction in the vessel.

Answer 9

False
Presence
Speed
Character of flow

Question 10

In practice, approximately _____ pulses are required to obtain one line of color Doppler information?

1
10
100
1000
1,000,000

Answer 10

10 (5-30)

Question 11

Lack of color in a vessel with blood flow may be attributable to ______ (multiple answers)

Low color gain
High wall filter setting
Low priority setting
Baseline shift
Aliasing

Answer 11

Low color gain
High wall filter setting
Low priority setting

Question 12

Increasing ensemble length ____ color sensitivity and accuracy and ________ FR.

Improves, increases
Degrades, increases
Degrades, decreases
Improves, decreases
None of the above

Answer 12

Improves, decreases

Question 13

What color control helps with clutter?

Answer 13

wall filter

Question 14

Color map baselines are always represented by what color?

Answer 14

black

Question 15

Steering the color window to the right or left changes _____

Frame rate
PRF
Doppler angle
Doppler shift
None of the above

Answer 15

Doppler angle and Doppler shift

Question 16

In a single frame, color can be different ( red and blue) in a vessel because of ____
Multiple answers

Vessel curvature
Sector format
Helical flow
Diastolic flow reversal

Answer 16

all

Question 17

Doppler power imaging indicates the _______ of flow

Presence
Direction
Speed
Character

Answer 17

Answer – presence

Question 18

If angle correction is set at 0 degrees but should be 60 degrees, the display indicates a flow speed of 100 cm/s
The correct flow speed is \_\_\_\_\_ cm/s.
 25
50
100
200
400

Answer 18

200

Question 19

If a 5-kHz Doppler shift corresponds to 100 m/s, a 2.5-kHz shift corresponds to ____ m/s

a. 100
b. 75
c. 50
d. 25

Answer 19

50

Question 20

Which of the following is increased if Doppler angle is increased?

a. Aliasing
b. Doppler shift
c. Effect of angle error
d. b and c
e. None of the above

Answer 20

effect of angle error

Question 21

Color-Doppler frame rates are ______ gray-scale rates .

a. equal to
b. less than
c. more than
d. depends on color map
e. depends on priority

Answer 21

less than

Question 22

Decreased distal resistance normally causes end diastolic flow to ________.

increase
decrease
be disturbed
become turbulent
more than one of the above

Answer 22

increase

Question 23

Flow reversal in diastole indicates ______.

a stenosis
an aneurism
high distal resistance
low distal resistance
more than one above

Answer 23

high distance resistance

Question 24

With angle correct incorporated, higher flow speed always produces a higher Doppler shift on spectral display.
T/F

Answer 24

True

Question 25

Higher operating frequency produces a higher Doppler shift on spectral display.
fD = (2 × f0× v)/c
True/false?

Answer 25

true

Question 26

Does higher freq transducer overestimate velocity?

Answer 26

no

Question 27

As stenosis progresses, which of the following increases?

Lumen diameter
Systolic Doppler shift
Diastolic Doppler shift
Spectral broadening
more than one of the above

Answer 27

Systolic Doppler shift
Diastolic Doppler shift
Spectral broadening

Question 28

Disturbed flow produces narrower spectrum.

Answer 28

false \

Question 29

Turbulent flow produces a narrower spectrum.

Answer 29

false

Question 30

If all the cells in a vessel were moving at the same constant speed, the spectral trace would be \_\_\_\_\_\_\_\_\_\_\_\_\_.
thin horizontal line
thick horizontal line
as in descending aorta 
tardus parvus
depends on velocity

Answer 30

thin horizontal line

Question 31

Stenosis affects \_\_\_\_\_\_\_\_\_\_\_\_.
Peak systolic flow speed
End diastolic flow speed
Spectral broadening
Window
Envelope
More than one of the above

Answer 31

all

Question 32

Doppler ultrasound provides information about flow conditions only at the site of measurement.

t/f?

Answer 32

false

Question 33

Doppler signal power (or amplitude) is proportional to _______.

Volumetric flow rate
Flow speed
The Doppler angle
Cell concentration
More than one of the above

Answer 33

cell concentration

Question 34

Compared with Doppler-shift imaging, Doppler-power imaging is _______.

More sensitive
Angle independent
Aliasing free
Speed independent
More than one of the above

Answer 34

all