Physical Principles Part 2

Question 1

A 7MHz pulse is attenuated _____ after it passes through 2cm of soft tissue

A. 5.5dB
B. 3.5dB
C. 14dB
D. 7dB

Answer 1

D, a wave travels 2cm x 7MHz x 0.5dB/cm/MHz= 7dB of attenuation

Question 2

Which of the following ultrasound techniques has the highest temporal resolution

A. 2D imaging
B. 3D imaging
C. M mode
D. color doppler

Answer 2

C

Question 3

Which of the following is more attenuating

A. moderately fatty liver
B. 2,5cm renal cyst
C. full urinary bladder
D. 2,5cm gallstone

Answer 3

D

Question 4

Which of the following sound / tissue interactions does NOT cause redirection of the incident wave

A. refraction
B. reflection
C. absorption
D. attenuation

Answer 4

C

Question 5

The SPL is 4mm. What is the minimum axial resolution

A. 1mm
B. 2mm
C. 8mm
D. 16mm

Answer 5

B, axial res= 1/2 SPL

Question 6

Spatial resolution is

A. highest with linear phased arrays
B. the weakest reflected signal the transducer can receive
C. the minimum reflector separation required to produce separate echoes
D. another term for slice thickness resolution

Answer 6

C

Question 7

If two calcifications are located side by side in the liver with a 3mm distance between them and the beam width is 6mm, how will the structures appear on the image

A. as a single elongated horizontal reflection
B. as two separate structures located 3mm apart on the image
C. as two separate structures located 6mm apart on the image
D. as a single elongated vertical reflection

Answer 7

A

Question 8

_______ is defined as the ratio of particle pressure to particle velocity at a given point within the US beam

A. rarefaction
B. dynamic range
C. impedance
D. compression

Answer 8

C

Question 9

If the amplitude of a wave is decreased by one half, the intensity _______

A. quadrupled
B. doubles
C. decreases to 1/4 the original intensity
D. decreases to 1/2 the original intensity

Answer 9

C, intensity is proportional to amplitude squared

Question 10

What system parameter is defined as the ability to differentiate two separate objects on an image

A. sensitivity
B. resolution
C. duty factor
D. rectification

Answer 10

B

Question 11

Multiplying density of the tissue by prop speed in the tissue will provide a value for what tissue characteristic

A. attenuation coefficient
B. intensity
C. frequency
D. acoustic impedance

Answer 11

D

Question 12

Which of the following imaging parameters is responsible for the ability to resolve the AP wall thickness of an artery

A. lateral resolution
B. dynamic range
C. contrast resolution
D. axial resolution

Answer 12

D

Question 13

Preferred levels of axial and lateral resolution will demonstrate

A. widely different numerical values
B. high numerical values
C. low numerical values
D. the same numerical value

Answer 13

C

Question 14

The unit used for the attenuation coefficient is

A. dB/cm/MHz
B. dB
C. dB/cm
D. mW/cm^2

Answer 14

C

Question 15

If more cycles are added to a pulse, which of the following types of resolution is degraded

A. axial
B. spatial
C. lateral
D. contrast

Answer 15

A

Question 16

Increasing the PRF improves

A. temporal resolution
B. the PRP
C. SPL
D. the pulse duration

Answer 16

A

Question 17

Curved PE elements and acoustic lenses will improve which two types of resolution

A. contrast and spatial
B. elevational and spatial
C. elevational and lateral
D. contrast and lateral

Answer 17

C

Question 18

A 5MHz transducer has a PRF of 6kHz and is being used to produce a wave with 0.6mm wavelength and 3mm spatial pulse length. What is the axial resolution of this system

A. 1.2mm
B. 1mm
C. 1.5mm
D. 2mm

Answer 18

C, Axial resolution= 1/2 SPL, AR=1/2 (3mm)=1.5mm

Question 19

Which of the pulses produced from a 7MHz transducer would have the best lateral and axial resolution

A. 2mm beam diameter, 8 pulses per cycle
B. 2mm beam diameter, 3 pulses per cycle
C. 8mm beam diameter, 8 pulses per cycle
D. 8mm beam diameter, 2 pulses per cycle

Answer 19

B, the more narrow the beam the better the lateral res, the shorter the pulse lengths the better the axial res

Question 20

Huygens principle describes

A. the change in wave direction when it crosses through dissimilar media
B. the relationship between pressure and velocity of blood flow in a vessel
C. the formation of the sound beam by multiple sound sources along the path of the beam
D. the appropriate guidelines for limiting ultrasound exposure

Answer 20

C

Question 21

What phenomenon is describes as the conversion of a pressure wave into an electrical voltage

A. snell’s effect
B. piezoelectric effect
C. schlierin effect
D. doppler effect

Answer 21

B

Question 22

_______ refers to redirection of a portion of the US beam from a boundary

A. rarefaction
B. absorption
C. reflection
D. refraction

Answer 22

C

Question 23

Which of the following frequencies could be detected by the human ear

A. 2500kHZ
B. 20MHz
C. 20kHz
D. 2000Hz

Answer 23

D

Question 24

Curved PE elements and acoustic lenses will improve which two types of resolution

A. contrast and spatial
B. elevational and spatial
C. contrast and lateral
D. elevational and lateral

Answer 24

D

Question 25

Which of the pulses produced from a 7MHz transducer would have the best lateral and axial resolution

A. 2mm beam diameter, 8 pulses per cycle
B. 8mm beam diameter, 8 pulses per cycle
C. 2mm beam diameter, 3 pulses per cycle
D. 8mm beam diameter, 2 pulses per cycle

Answer 25

C