Basic Principles of Ultrasound Exam

Question 1

If amplitude is double, intensity is ____
a. doubled
b. unchanged
c. halved
d. quadrupled

Answer 1

d. quadrupled

Question 2

A unit for intensity is ____
a. cm/MHz
b. mW/cm2
c. mHz/cm2
d. mm/cm2

Answer 2

b. mW/cm2

Question 3

Because diagnostic ultrasound pulses are usually two or three cycles long, axial resolution is usually equal to ____ to ____ wavelengths.
a. 4,6
b. 1, 3.5
c. 1, 1.5
d. 2, 3

Answer 3

c. 1, 1.5

Question 4

With perpendicular incidence, the reflected intensity depends on the ____.
a. density difference
b. impedance difference
c. impedance sum
d. b and c
e. a and b

Answer 4

d. b and c

Question 5

Induced acoustic-emission effects are independent of:
a. Doppler shifts
b. microbubble size
c. contrast motion
d. all of the above

Answer 5

c. contrast motion

Question 6

SPL is the ____ of _____ that a pulse occupies while it travels
a. amount, amplitude
b. length, space
c. length, time
d. intensity, energy

Answer 6

b. length, space

Question 7

In harmonic-imaging mode, the echoes from the oscillating microbubbles have a:
a. low singal-to noise ratio
b. low transducer frequency
c. equal signal-to-noise ration
d. high signal-to noise ratio

Answer 7

d. high signal-to noise ratio

Question 8

Sound travels most slowly in _____
a. liquids
b. gases
c. bone
d. tissue

Answer 8

b. gases

Question 9

If the intensity of 40-MHz ultrasound entering soft tissue is 2 W/cm2, the intensity at a depth of 4 cm is ___________ W/cm2.
a. 0.00000002
b. 0.0000002
c. 0.00002
d. 0.000002

Answer 9

a. 0.00000002( attenuation 8db intensity ratio 0.16)

Question 10

PD is the ____ it takes for a pulse to occur.
a. period
b. duration
c. time
d. frequency

Answer 10

c. time

Question 11

Ultrasound transducers convert ____ energy into ___ energy, and vice versa.
a. heat, light
b. electric, light
c. heat, electric
d. electric, ultrasound

Answer 11

d. electric, ultrasound

Question 12

If a 6 MHz transducer images to a depth of 10 cm, to avoid range ambiguity, the maximum PRF permitted is ______.
a. 7.7 kHz
b. 6.0 kHz
c. 10.0 kHz
d. 1.54 MHz

Answer 12

a. 7.7 kHz

Question 13

How many cycles are there in 1 second of continuous wave of 5 MHz ultrasound?
a. 5
b. 500
c. 5000
d. 5,000,000
e. none of the above

Answer 13

d. 5,000,000

Question 14

The principle on which ultrasound transducers operate is the ____
a. Acouto-optic effect
b. Acoustoelectric effect
c. Piezoelectric effect
d. Doppler effect
e. Cause and effect

Answer 14

c. Piezoelectric effect

Question 15

If the input power is 1 mW and the output is 10,000 mW, the gain is ____dB.
a. 10
b. 20
c. 30
d. 40

Answer 15

d. 40

Question 16

Pulsed wave Doppler has what advantage over continuous wave Doppler?
a. Two side-by-side piezoelectric elements in one transducer permit duplex scanning
b. It has range resolution and eliminates range ambiguity
c. It eliminates aliasing when measuring high velocities
d. The pulse length is infinite in length

Answer 16

c. It eliminates aliasing when measuring high velocities

Question 17

The wavelength of 7-MHz ultrasound in soft tissues is ____mm.
a. 0.54
b. 3.33
c. 1.54
d. 0.22

Answer 17

d. 0.22

Question 18

The piezoelectric effect describes how ____ is converted into ____ by a ____.
a. electricity, an image, display
b. incident sound, reflected sound, boundary
c. ultrasound, electricity, transducer
d. ultrasound, heat, tissue
e. none of the above

Answer 18

c. ultrasound, electricity, transducer

Question 19

If a display has a dynamic range of 20 dB and the smallest voltage it can handle is 200 mV, then the largest voltage it can handle is ______________________ V.
a. 20
b. 2.0
c. 0.2
d. 0.02

Answer 19

b. 2.0

Question 20

Based on the following information put together, the DF is ____. The PD in soft tissue for a two-cycle pulse of frequency 5 MHz is ___. For a 1-kHz, the PRP is ____ms.
a. 0.0004
b. 0.004
c. 0.4
d. 0.04

Answer 20

0.0004