Questions 1 - Lange Review Ultrasonography Examination, 4th Edition

Lange Review Ultrasonography Examination, 4th Edition

Questions

GENERAL INSTRUCTIONS: For each question, select the best answer. Select only one answer for each question unless otherwise specified.

1. Which of the following is the standard protocol for digital imaging that allows compatibility and communication between computers, workstations, and network hardware provided by various manufacturers of CT, MRI, and ultrasound equipment?

(A) SDMS

(B) PACS

(D) DICOM

(E) ALARA

2. The spatial pulse length

(A) determines the speed of ultrasound in tissue

(B) usually increases with higher frequency

(D) determines lateral resolution

(E) usually decreases with higher frequency

3. Axial resolution is improved by

(A) focusing

(B) acoustic mirrors

(D) beam diameter

(E) damping

4. Lateral resolution is improved by

(A) ring-down

(B) decreased beam diameter

(D) imaging in the far zone

(E) damping

5. The beam of an unfocused transducer diverges

(A) because of inadequate damping

(B) in the Fresnel zone

(D) when the pulse length is long

(E) at the dead zone

6. Reverberation artifacts are a result of

(A) electronic noise

(B) improper time gain compensation (TGC) settings

(D) duplication of a true reflector

(E) absence of echo information distal to a reflector

7. The recommendations for reducing the potential for bioeffects using the ALARA principle is to

(A) increase receiver gain and decrease the power output

(B) increase power output and decrease transducer frequency

(D) decrease scanning time when a patient has a maternal temperature and decrease overall gain and increase power output

(E) use an unfocused transducer and increase the scan time

8. What technique can be employed to reduce grating side lobes?

(A) depolarization

(B) apodization

(D) magnification

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

(A) coded excitation

(B) harmonic imaging

(D) subdicing

(E) magnification

10. A 75-year-old patient suffering from Alzheimer’s disease arrived in the ultrasound department from the surgical ward for ultrasound of the right legs to rule out deep venous thrombosis. The patient has no name band. What is the most appropriate next step?

(A) retrieve the name and medical record number from the chart that accompanied the patient.

(B) return the patient to the ward for appropriate identification and tagging.

(D) call the nurse on the floor by telephone to identify the patient.

(E) put an ID wristband on the patient that matches the name sent to you.

Questions 11 through 15: Match the following group of wires with its function for the AIUM test object (Fig. 1–51).

11. registration or B-mode alignment _____

12. axial resolution _______

13. lateral resolution _______

14. dead zone _______

15. depth calibration _______

16. Decreasing the spatial pulse length

(A) reduces the field of view

(B) reduces lateral resolution

(D) improves lateral resolution

(E) reduces axial resolution

FIGURE 1–51.

17. How much will a 3.5 MHz pulse be attenuated after passing through 2 cm of soft tissue?

(A) 7 dB

(B) 3.5 dB

(D) 1.75 dB

(E) 5.3 dB

18. Propagation speed errors result in

(A) reverberation

(B) improper axial position

(D) a Doppler shift

(E) all of the above

19. Enhancement is caused by

(A) reduction in echo amplitude distally

(B) propagation speed errors

(D) weakly attenuating structures

(E) duplication of echoes on the opposite side of a strong reflector

20. The Doppler shift frequency is

(A) directly proportional to the velocity of the reflector

(B) greater in pulsed Doppler systems

(D) dependent on the number of transducer elements being used

(E) indirectly proportional to the velocity of the reflector

21. The number of frames per second necessary for a real-time image to be flicker free is

(A) more than 15

(B) less than 1

(D) between 2 and 5

22. A non-English-speaking patient presented for an ultrasound-guided breast biopsy in which an informed consent is required. What is the most appropriate step to take?

(A) get a family member who speaks the patient’s language to be an interpreter.

(B) use a sign-language interpreter licensed for the deaf and hearing impaired.

(D) get a physician who is scheduled to perform the ultrasound examination.

(E) use a certified language line.

23. The intensity of the ultrasound beam is usually greater at the focal zone because of

(A) decreased attenuation

(B) smaller beam diameter

(D) a shorter duty factor

(E) larger beam diameter

24. If the amplitude is doubled, the intensity is

(A) doubled

(B) cut in half

(D) unchanged

(E) decreased by four times

25. The attenuation for soft tissue is

(A) increased with tissue thickness

(B) determined by the slope of the TGC curve

(D) unimportant when using digital scan converters

(E) decreased with high frequency

26. The acoustic impedance of the matching layer

(A) can be chosen to improve transmission into the body

(B) must be much larger than the transducer material to reduce attenuation

(D) must be made with the same material as the damping material

(E) must be smaller than the impedance of the tissue

27. Which of the following is necessary additional confirmation required to ensure that the patient you are about to scan is the correct patient?

(A) which ward the patient is from

(B) documented ultrasound request

(D) date of birth

(E) type of ultrasound study

28. If a patient’s body fluids (blood or vaginal secretions) come into contact with the ultrasound machine, what would be the most appropriate action?

(A) cancel the cases for the day and wait for the blood to dry before cleaning the machine.

(B) document the date and time and call the biomedical department.

(D) use approved disinfectant solution to clean the machine.

(E) the ultrasound machine should be regarded as contaminated waste and should be replaced with a new ultrasound machine.

29. The operating frequency

(A) depends on the transducer’s ring-down time

(B) depends on the thickness of the crystal

(D) depends on the strength of the pulser

(E) all of the above

30. The period of an ultrasound wave is

(A) the time at which it is no longer detectable

(B) the number of times the wave is repeated per second

(D) the speed of the wave

(E) the peak pressure of the wave

31. The dynamic range of a system

(A) is increased when specular reflectors are scanned

(B) is decreased when shadowing is present

(D) is the ratio of smallest to largest power level that the system can handle

(E) the difference between the smallest and largest signals measured

32. What term describes a digital imaging system that enables ultrasound, x-ray, MRI, and CT images to be stored electronically and viewed remotely on a workstation?

(A) high-definition hormonic imaging

(B) coded excitation digital imaging protocol

(D) DICOM

(E) PACS

33. Increasing the pulse repetition period

(A) improves resolution

(B) increases the maximum depth that can be imaged

(D) increases refraction

(E) all of the above

34. Ultrasound bioeffects with an unfocused beam

(A) do not occur

(B) cannot occur with diagnostic instruments

(D) are not confirmed above 1 W/cm² SPTA

35. When can an informed consent be revoked?

(A) after 72 hours for an adult older than 21 years

(B) at any time

(D) cannot be revoked after signing, because it is a legally binding document

(E) 24 hours after signing the document if the patient is currently hospitalized

36. What is the first thing you should do when a patient enters the ultrasound room?

(A) introduce yourself with name and title

(B) disinfect the transducer

(D) check the ultrasound machine for electrical safety

(E) find the protocol for the ultrasound procedure

37. How often should you disinfect the transvaginal transducer?

(A) once a week

(B) every day at the end of the work shift

(D) if the patient has a vaginal infection or bleeding

(E) after each use

38. Which of the following should be minimized in order to comply with the ALARA principle?

(A) time gain compensation (TGC)

(B) overall gain

(D) transmit power

(E) magnification

39. Which of the following best describes autocorrelation?

(A) mathematical process in which a waveform is multiplied by a time-shifted version of itself.

(B) the automatic correlation between the transmitted echo and the reflected echo.

(D) the continuously repeated display of a recorded image from memory.

(E) a pulsed Doppler system that enables velocity measurements at several depths simultaneously.

40. What is the name of the mechanism of ultrasound bioeffects in which microbubbles oscillate without collapsing?

(A) stable

(B) ionization

(D) fluid streaming

(E) transient

41. Which of the following would not typically be related to ultrasound bioeffects?

(A) power output

(B) thermal index (TI)

(D) high-frequency transducer

(E) mechanical index (MI)

42. Harmonic frequencies are derived from

(A) nonlinear wave propagation

(B) perpendicular wave propagation

(D) proportional behavior

(E) linear wave propagation

43. Which of the following has an effect on the propagation speed of the ultrasound?

(A) high-frequency transducers

(B) output power

(D) tissue type

(E) time gain compensation (TGC)

44. Which of the following is equivalent to the prefix giga?

(A) 10⁶

(B) 10^–6

(D) 10³

(E) 10^–9

45. What percentage of intensity of an ultrasound pulse incident on an interface of 0.25 and 0.75 rayls is reflected?

(A) 50%

(B) 100%

(D) 75%

(E) 15%

46. Axial resolution can be improved by

(A) higher frequency transducers

(B) lower frequency transducers

(D) poorly damped transducers

(E) focusing the ultrasound beam in the near zone

47. When particle motion of a medium is parallel to the direction of a wave propagation, what is the wave being transmitted called?

(A) longitudinal wave

(B) shear wave

(D) electromagnetic wave

(E) transverse wave

48. The wavelength in a material having a wave velocity of 1,500 m/s employing a transducer frequency of 5 MHz is

(A) 0.3 mm

(B) 0.3 cm

(D) 0.6 cm

(E) 3.0 cm

49. Which of the following determines the amount of reflection at the interface of two dissimilar materials?

(A) the index of refraction

(B) the frequency of the ultrasonic wave

(D) the difference in specific acoustic impedances

(E) time gain compensation (TGC)

50. Which equation describes the relationship among wave propagation speed, wavelength, and frequency?

(A) V = f λ

(B) wavelength = 2(frequency × velocity)

(D) wavelength = frequency + velocity

(E) λ = r × f

51. When a sound wave strikes a tissue interface at an oblique angle of incidence, what other condition must be present in order for refraction to occur?

(A) a change in the angle of reflection

(B) a difference in propagation speeds

(D) the presence of several small reflectors

(E) normal incidence

52. The acoustic impedance of a material is

(A) directly proportional to density and inversely proportional to velocity

(B) directly proportional to velocity and inversely proportional to density

(D) equal to the product of density and velocity

(E) unrelated to velocity and density

53. What is the average velocity of ultrasonic waves in soft tissue?

(A) 1,540 m/s

(B) 154,000 cm/s

(D) about one mile per second

(E) all of the above

54. A soft tissue mass is measured to be 80 mm in diameter; what is the diameter in centimeters?

(A) 80.00 cm

(B) 8.0 cm

(D) 0.8 cm

(E) 0.08 cm

55. When a sound wave strikes a boundary between two tissues with a normal incidence, what other condition must be present in order for reflection to occur?

(A) an oblique incidence

(B) a difference in acoustical impedance

(D) a thick boundary

(E) the two media must have identical impedances

56. Ultrasound transducers convert

(A) mechanical to thermal energy and vice versa

(B) thermal to cavitation energy and vice versa

(D) heat to electromagnetic energy and vice versa

(E) mechanical to electrical energy and vice versa

57. The velocity of sound waves is primarily dependent on

(A) angulation

(B) reflection

(D) frequency

(E) acoustic power and the time gain compensation (TGC)

58. Increasing the frequency of an ultrasonic longitudinal wave will result in which of the following changes in the velocity of the wave?

(A) an increase

(B) a decrease

(D) a reversal

(E) increase at first and then a decrease

59. Which of the following terms describes the change in direction of an ultrasonic beam when it passes from one medium to another in which elasticity and density differ from those of the first medium?

(A) refraction

(B) rarefaction

(D) reflection

(E) compression

60. A long near zone can be obtained by

(A) using a higher-frequency transducer

(B) adding a convex lens to the transducer

(D) increasing the damping

(E) using a low-frequency transducer

61. If a 2 MHz frequency is used in human soft tissue, what is the approximate wavelength?

(A) 0.75 mm

(B) 0.15 mm

(D) 0.44 mm

(E) 2.75 mm

62. What is the ratio of particle pressure to particle velocity at a given point within the ultrasonic field?

(A) interference

(B) impedance

(D) interface

(E) intensity

63. What is the following formula used to determine?

(A) shift in frequency caused by the Doppler effect

(B) degree of attenuation

(D) amount of amplification necessary to produce diagnostic ultrasound

(E) frequency related to wavelength

64. The principle that states that all points on a wavefront can be considered as point sources for the production of spherical secondary wavelets was postulated by

(A) Doppler

(B) Young

(D) Rayleigh

(E) Snell

65. A 10-dB difference in signal intensity is equivalent to which of the following?

(A) twofold

(B) tenfold

(D) 1000-fold

(E) one-tenth

66. The level below which signals are not processed through an ultrasound receiver system is the

(A) wall filter level

(B) reject level

(D) dynamic range level

(E) digitizing level

67. Term for signal dynamic range reduction.

(A) rejection

(B) compression

(D) elimination

(E) sensitivity

68. An ultrasound system mode that displays an upward displacement from a baseline that is proportional to the strength of the echo.

(A) A-mode

(B) B-mode

(D) M-mode

(E) C-mode

69. Which of the following is not a method for restricting the dynamic range of the ultrasound signal?

(A) threshold

(B) rejection

(D) relaxation

70. Which of the following types of scan converter is used in current ultrasound systems?

(A) analog

(B) digital

(D) static

(E) mechanical

71. Which of the following terms describes the fraction of time that pulsed ultrasound is actually on?

(A) duty factor

(B) frame rate

(D) pulse repetition period

(E) pulse stretching

72. Which of the following is a system performance parameter that is assessed using a multipurpose phantom to determine the minimum echo amplitude that can be detected?

(A) compression

(B) demodulation

(D) sensitivity

(E) dead zone

73. Which of the following image shapes is produced by a linear sequenced array real-time transducer?

(A) pie shape

(B) rectangular

(D) triangular

(E) trapezoidal shape

74. The major factor in determining the acoustic power output of the transducer is the

(A) size of the transducer

(B) magnitude of the pulser voltage spike

(D) amount of gain

(E) amount of magnification

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

(A) frame rate and field of view (FOV)

(B) time gain compensation (TGC) and overall gain

(D) thermal index and mechanical index

(E) ensemble length and focal depth

76. Which of the following relates to bandwidth and operating frequency?

(A) near zone

(B) piezoelectric crystal

(D) far zone

(E) matching layer

77. The extraneous beams of ultrasound not in the direction of the main axis specific to multielement transducer arrays are called

(A) apodization zones

(B) subdiced beams

(D) harmonic lobes

(E) grating lobes

78. The actual time from the start of the pulse to the end of the pulse is known as

(A) pulse repetition frequency

(B) pulse pressure

(D) pulse duration

(E) spatial pulse length

79. Arrange the given units in increasing order: nano, micro, milli, and centi.

(A) 10^–9, 10⁶, 10², 10³

(B) 10^–9, 10^–6, 10^–3, 10^–2

(D) 10^–2, 10^–1, 10³, 10^–3

(E) 10⁹, 10⁶, 10³, 10²

80. Specular reflection occurs when

(A) the frequency is small compared with the wavelength

(B) the object that causes the reflection is small relative to the wavelength

(D) the angle of incidence and the angle of reflection differ by at least 45°

(E) irregular or rough interfaces resulting in sound waves traveling in many directions

81. The refractive index of water is slightly altered when a sound beam passes through it, thus causing compression and rarefaction of the water molecules.

The phenomenon is the basis for what technique used to make ultrasound beam measurements?

(A) radiation force balance

(B) Schlieren photography

(D) autocorrelation

(E) cross-correlation

82. Artifacts appearing as parallel, equally spaced lines are characteristic of

(A) acoustic shadowing

(B) off-normal incidence

(D) reverberation

(E) enhancement

83. An increase in reflection amplitude from reflectors that lie behind a weakly attenuating structure is called

(A) the incidence angle

(B) enhancement

(D) the effective reflecting area

(E) shadowing

84. The amount of dispersion in the far field of an ultrasound beam can be decreased by

(A) using a transducer with a convex face

(B) using a larger diameter transducer

(D) using a lower frequency transducer

(E) using a smaller diameter transducer

85. Longitudinal or axial resolution is directly dependent on

(A) depth of penetration

(B) spatial pulse length

(D) the angle of incidence

(E) ultrasound beam width

86. Which of the following ultrasound frequency spectrum is specifically equal to operating frequency divided by bandwidth?

(A) frequency limit

(B) Q-factor

(D) frequency duration

(E) harmonic factor

87. The type of transducer that combines the technology of linear sequence and phased array to produce a trapezoidal-shaped image is called

(A) rectangular array

(B) multi-function array

(D) linear curved array

(E) vector array

88. Which of the following is the least attenuating material to the transmission of ultrasound?

(A) muscle

(B) liver

(D) kidney

(E) urine

89. The ratio of the largest power to the smallest power that the ultrasound system can handle is the

(A) dynamic range

(B) overall gain

(D) amplification factor

(E) frequency factor

90. Ultrasound waves in tissues are called

(A) shear waves

(B) electromagnetic waves

(D) longitudinal waves

(E) transverse waves

Questions 91 through 99 refer to Fig. 1–52.

FIGURE 1–52.

91. The row of wires in the middle are used to check

(A) lateral resolution

(B) axial resolution

(D) horizontal distance calibration

(E) all of the above

92. Which of the diagrams shows correct registration?

(A) scan A

(B) scan B

(D) all of the above

(E) none of the above

93. The row of wires on top is used to check

(A) dead zone

(B) vertical distance calibration

(D) axial resolution

(E) registration

94. The speed of ultrasound in the AIUM test object is equivalent to

(A) the speed of typical fatty tissue

(B) the speed of blood

(D) the speed in soft tissue

(E) the speed of sound of the stainless steel rods within the test object

95. The row of wires on the bottom is used to check for

(A) axial resolution

(B) lateral resolution

(D) vertical distance calibration

(E) dead zone

96. Which of the following cannot be checked when the test object is scanned from the top only?

(A) axial resolution

(B) lateral resolution

(D) horizontal distance calibration

(E) dead zone

97. Which of the following parameters cannot be evaluated by the AIUM test object?

(A) gray scale

(B) dynamic range

(D) scattering characteristics

(E) all of the above

98. Scanning a test object from multiple sides could be used to check

(A) gray scale

(B) depth resolution

(D) registration

(E) all of the above

99. When using the AIUM test object, which of the following should be kept constant for comparisons?

(A) output power

(B) Time gain compensation (TGC)

(D) transducer, megahertz, and focus

(E) all of the above

100. Which of the following types of cavitation can result in highly localized temperature elevation up to 10,000 degrees Kelvin?

(A) transient

(B) pressure

(D) velocity

(E) frequency

101. There are many types of natural and synthetic crystals that possess and exhibit piezoelectric properties. Which of the following are not natural?

(A) tourmaline

(B) quartz

(D) lithium sulfate

102. Which one of the following materials would not be suitable as acoustic insulators for a pulse transducer backing?

(A) cork

(B) rubber

(D) araldite loaded with tungsten powder

(E) epoxy resin

103. When using a continuous-wave ultrasound, which of the following intensities are equal?

(A) SPTP = SATP

(B) SATP = SPTP

(D) SPTP = SPPA

104. If the frequency of sound is below 20 Hz, what is it called?

(A) infrasound

(B) audible sound

(D) x-rays

(E) supersonic

105. If the frequency of sound is above 20 kHz, what is it called?

(A) infrasound

(B) ultrasound

(D) x-rays

(E) subsonic

106. If the frequency of sound is between 20 Hz and 20 kHz, what is it called?

(A) x-rays

(B) audible sound

(D) infrasound

(E) supersonic

107. Which of the following is not among the spectrum of electromagnetic waves?

(A) x-rays

(B) ultrasound

(D) infrared

(E) visible light

108. The term hertz denotes

(A) strength of the ultrasound waves

(B) the distance that ultrasound waves travel through a medium

(D) cycles per second

(E) the pressure or height of a wave

109. Which one of the following Doppler interrogation of a vessel will possibly yield no Doppler shift?

(A) 10°

(B) 60°

(D) 30°

(E) 0°

110. Which of the following is an example of a transducer?

(A) battery

(B) loudspeaker

(D) human being

(E) all of the above

111. When constant electrical voltage is applied across the thickness of a piezoelectric crystal, the crystal will

(A) always increase in size

(B) always decrease in size

(D) increase or decrease in size depending on the voltage polarity

(E) cause a Curie temperature elevation and result in depolarization

112. The abbreviation 5 MHz denotes

(A) five hundred thousand cycles per second

(B) five hundred million cycles per second

(D) five million cycles per second

(E) 5 Hz

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

(A) reduce pulse duration

(B) improve axial resolution

(D) improve lateral resolution

(E) A and B only

(F) A and D only

(G) A, B, and C only

114. What is the average speed of ultrasound in human soft tissue at 37°C?

(A) 1,540 meters per second

(B) 1,540 miles per second

(D) 154,000 meters per minute

(E) 1.54 centimeters per second

115. In physical science, the word period denotes

(A) the pressure or height of a wave

(B) the speed of a wave per cycle

(D) the distance it takes for one cycle to occur

(E) the number of times the wave is repeated per second

116. What direction is the motion of particles in a longitudinal wave

(A) motion of particles is parallel to the axis of wave propagation

(B) motion of particles is perpendicular to the axis of wave propagation

(D) motion of particles travels to the surface vibrating particles

(E) motion of particles travels clockwise circle to the axis of wave propagation

117. What direction is the motion of particles in a transverse wave

(A) motion of particles is parallel to the axis of wave propagation

(B) motion of particles travels counter-clockwise ellipse to the axis of wave propagation

(D) motion of particles travels to the surface vibrating particles

(E) motion of particles travels clockwise circle to the axis of wave propagation

118. Ultrasound wave propagation causes displacement of particles in a medium. What are the regions of greatest particle concentration called?

(A) reaction

(B) compression

(D) attenuation

(E) reflection

119. Ultrasound wave propagation causes displacement of particles in a medium. What are the regions of lowest particle concentration called?

(A) compression

(B) condensation

(D) attenuation

(E) rarefactions

120. Which of the following disclosures cannot be made without an authorization signed by the patient?

(A) reporting child abuse

(B) response to court orders

(D) reporting fraud or abuse of public funds

(E) accidental gunshot wound

121. Which of the following is related to axial resolution

(A) the ability to distinguish two objects separated in the direction of the ultrasound beam

(B) the ability to distinguish two objects separated in the direction perpendicular to the ultrasound beam

(D) the same as azimuthal, angular, and transverse resolution

(E) both A and D

(F) both A and C

122. Which of the following is related to lateral resolution?

(A) the same as depth, longitudinal and range resolution

(B) the ability to distinguish two objects separated in the direction perpendicular to the ultrasound beam

(D) the same as azimuthal, angular, and transverse resolution

(E) both A and B

(F) both B and D

Questions 123 through 128: Match the structures in Fig. 1–53 with the list of parts given.

123. _______ (A) matching layer

124. _______ (B) damping (backing) material

125. _______ (C) connector

126. _______ (D) piezoelectric element

127. _______ (E) plastic case

128. _______ (F) electrode

FIGURE 1–53.

129. What does the arrow in Fig. 1–54 on the following page point to?

(A) near gain

(B) far gain

(D) power output

(E) zoom-level controls

FIGURE 1–54.

130. When making circumference measurements using electronic calipers in diagnostic ultrasound, the results are expressed in what type of unit?

(A) millimeter or centimeter (cm)

(B) centimeter squared (cm²)

(D) meter cubed (m³)

(E) millimeter cubed (mm³)

131. Implementation of apodization in diagnostic ultrasound systems requires

(A) acoustic lens between each element

(B) different voltages to be applied to each element

(D) depolarization of the transducer elements

(E) increasing the fundamental frequency

132. This multipurpose phantom is used to evaluate what target group, arrow A (Fig. 1–55)?

(A) ring down

(B) gray-scale and displayed dynamic range

(D) vertical measurement calibration

(E) axial resolution

FIGURE 1–55.

133. This multipurpose phantom is used to evaluate what target group, arrow B (Fig. 1–55)?

(A) dead zone

(B) gray scale

(D) displayed dynamic range

(E) axial resolution

134. This multipurpose phantom is used to evaluate what target group, arrow D (Fig. 1–55)?

(A) dead zone

(B) gray scale

(D) displayed dynamic range

(E) axial resolution

135. Which one of the following does not improve temporal resolution?

(A) low-line density

(B) higher frame rate

(D) fewer pulse per frame

(E) increasing depth

136. Which of the following is true about the dynamic aperture when it is increased in size?

(A) the beam will always focus at a greater depth.

(B) near-zone length increases.

(D) lateral resolution is unchanged.

(E) all of the above.

137. Which of the following terms denotes the technique of dividing normal crystal elements into smaller elements?

(A) coded excitation

(B) apodization

(D) subdicing

(E) autocorrelation

138. Which of the following materials is used as a backing material in continuous-wave transducers?

(A) epoxy resin

(B) tungsten

(D) air

(E) barium sulfate

139. Which of the following converts Doppler shift information into visual analysis?

(A) autocorrelation

(B) hue

(D) reject control

(E) saturation

140. The second harmonic frequency is

(A) frequency of second reverberation echo

(B) fundamental frequency plus the transmitted frequency

(D) twice the fundamental frequency

(E) never recorded

141. If frequency is doubled, the wavelength will

(A) double

(B) increase by a factor of four

(D) become shorter by one-fourth

(E) become shorter by one-half

142. If frequency is reduced by a factor of two, the wavelength will

(A) double

(B) increase by a factor of four

(D) become shorter by one-forth

(E) become shorter by one-half

143. As frequency increases, the penetration will

(A) decrease

(B) increase

144. In general, if frequency increases, the resolution will

(A) decrease

(B) increase

145. For an unfocused transducer, if frequency increases, the beam width will

(A) decrease

(B) increase

146. Ultrasound generally has most difficulty propagating through

(A) lung

(B) blood

(D) IVP contrast

(E) all of the above

(F) A and C only

(G) A and B only

147. Which of the following can be used as a coupling medium?

(A) water

(B) saline

(D) aqueous gels

(E) all of the above

148. Attenuation denotes

(A) progressive weakening of the sound beam as it propagates through a medium

(B) progressive decrease of speed of sound in the tissues

(D) progressive bending of the ultrasound beam after crossing an interface

(E) progressive decrease in frequency

149. The piezoelectric effect is the

(A) depolarization of tissue following sonication

(B) mechanical deformation of ultrasound crystal that results from a high voltage applied across the crystal thickness

(D) the depolarization of the ultrasound crystal following heating

(E) deformation of soft tissue following sonication

150. The reverse piezoelectric effect can be best described as

(A) depolarization of tissue following sonication

(B) mechanical deformation of ultrasound crystal that results from a high voltage applied across the crystal thickness

(D) the depolarization of the ultrasound crystal following heating

(E) deformation of soft tissue following sonication

151. The parameter used to express attenuation coefficient is

(B) 0.5 dB/cm/MHz

152. The ultrasound wave results in the transfer of which of the following through tissue?

(A) particles

(B) matter

(D) mass

(E) ionizing radiation

153. The type of compressional wave in which the particles move back and forth parallel to the direction of wave propagation is known as

(A) longitudinal wave

(B) heat waves

(D) surface wave

(E) electromagnetic wave

154. Wavelength is a measure of

(A) time

(B) voltage

(D) pulse duration

(E) exposure

155. Ultrasonic waves are

(A) compressional

(B) x-ray

(D) solar

(E) transverse

156. Acoustic impedance is

(A) the amount of tissue × the speed of sound in tissue

(B) the density of tissue × the speed of sound in tissue

(D) the distance from one interface to the next

(E) mass per unit volume

FIGURE 1–56.

157. What does the arrow (A) point to in this color variance map (Fig. 1–56)?

(A) blood cells moving toward the transducer

(B) blood cells moving away from the transducer

(D) turbulent Doppler flow

(E) laminar flow

158. What is the typical frequency of medical ultrasound transducers?

(A) less than 20 Hz

(B) less than 20 kHz

(D) greater than 20,000 Hz but less than 2,000,000 Hz

(E) greater than 1 MHz

159. Period is inversely proportional to

(A) velocity

(B) power

(D) frequency

(E) none of the above

160. As the ultrasound beam becomes more perpendicular to an organ interface

(A) scattering becomes greater

(B) there are more refracted echoes

(D) the received echoes will be larger

(E) the received echoes will be smaller

161. A decibel (dB) is proportional to the

(A) ratio of two sound intensities

(B) sum of two sound intensities

(D) velocity of the sound wave

(E) the difference between the transmitted and the received frequency

162. Axial resolution is also known as all of the following except

(A) depth

(B) range

(D) longitudinal

(E) radial

163. Which of the following has the highest sound velocity?

(A) soft tissue

(B) femur

(D) water

(E) blood

164. According to the AIUM, no significant biologic effects have been proved in mammals using a focused transducer with exposures of

(A) SPTA intensities above 100 mW/cm²

(B) SPTA intensities below 100 mW/cm²

(D) SATP intensities below 10 mW/cm²

(E) SPTA intensities below 1 W/cm²

165. In addition to penetration, what does coded excitation improve?

(A) frame rate

(B) signal-to-noise ratio

(D) angular resolution

(E) Doppler shift

166. Which of the following has the lowest intensity?

(A) SPTP

(B) SATP

(D) SATA

(E) SPPA

167. What is the definition of the beam uniformity ratio?

(A) the spatial average intensity divided by the spatial intensity

(B) the spatial peak intensity divided by the spatial average intensity

(D) the temporal peak intensity divided by the spatial peak intensity

(E) none of the above

168. The duty factor of a pulsed echo system is normally less than

(A) 5%

(B) 100%

(D) 25%

(E) 99%

169. A shortened spatial pulse length results in

(A) better lateral resolution

(B) lower frequency

(D) better axial resolution

(E) increased side lobes

170. The equation for measuring the relationship among propagation speed, frequency, and wavelength is

(E) Z = pc

171. Attenuation of an ultrasound beam can occur by

(A) divergence of the beam

(B) scattering

(D) all of the above

172. Which of the following units is used for an ultrasound attenuation coefficient?

(A) dB/cm/MHz

(B) dB/cm²/Hz

(D) m/dB/cm³

(E) dB/P/W/cm

173. If the transducer Q factor is low, which of the following is true about the bandwidth?

(A) narrow

(B) wide

174. Axial resolution can be improved by

(A) reducing the spatial pulse length

(B) increasing the spatial pulse length

(D) focusing

175. Which of the following primarily affects axial resolution?

(A) beam width

(B) spatial pulse length

(D) acoustic lens

(E) focusing

176. Which of the following may improve both axial and lateral resolution?

(A) short pulse length

(B) narrow beam width

(D) increased transducer frequency

177. Which of the following is not another term for lateral resolution?

(A) azimuthal

(B) transverse

(D) angular

178. What is the duty factor of continuous-wave Doppler?

(A) less than 1%

(B) 100%

(D) 50%

(E) 10%

179. What does the arrow (B) point to in this color variance map (Fig. 1–57)?

(A) blood cells moving toward the transducer

(B) blood cells moving away from the transducer

(D) veins

(E) arteries

FIGURE 1–57.

180. Acoustic impedance may be expressed using which of the following units?

(A) pascals

(B) meters/dB

(D) rayls

(E) Hz

181. Which of the following is the most obvious application of C-mode?

(A) cardiac imaging

(B) 3D

(D) 4D

182. The height of the vertical spike in an A-mode display corresponds to

(A) the strength of the echo

(B) the distance to the reflector

(D) the pulse repetition frequency

(E) Doppler shift

FIGURE 1–58.

183. What does the arrow (C) point to in this color variance map (Fig. 1–58)?

(A) blood cells moving toward the transducer

(B) blood cells moving away from the transducer

(D) veins

(E) arteries

184. Which of the following equations is used for calculating the percentage of the reflected intensity at an interface?

(E) Z = pV

185. The reflection coefficient between water and air is approximately:

(A) 1%

(B) 50%

(D) 100%

(E) 0%

186. What happens to the ultrasound beam beyond the critical angle?

(A) 100% is transmitted

(B) 100% is reflected

(D) 75% is reflected, 25% is transmitted

(E) 100% refracted

187. Rayleigh scattering occurs if the particle dimensions are

(A) less than the wavelength

(B) greater than the wavelength

188. Which of the following will increase the dead-zone length?

(A) use of an acoustic standoff pad

(B) higher frequency transducer

(D) increased spatial pulse length

(E) increased output power

189. Power is defined as energy per unit

(A) mass

(B) distance

(D) force

(E) work

190. The ability to resolve structures lying perpendicular to the axis of the ultrasound beam is called

(A) lateral resolution

(B) axial resolution

(D) orthogonal resolution

191. In most soft tissues, the attenuation coefficient varies approximately

(A) inversely with frequency

(B) with the square of the frequency

(D) directly with frequency

192. Ultrasound absorption in a medium results in

(A) conversion of ultrasound energy into heat

(B) dissipation of ultrasound energy into x-rays

(D) dissipation of ultrasound energy into gamma rays

193. The typical value of one-way attenuation in soft tissue is

(A) 1 dB/cm²/Hz

(B) 2 dB/cm/Hz

(D) 0.5 dB/cm/MHz

(E) 10 dB/mm/MHz

194. Which of the following produces false echoes that are occasionally seen in fluid-filled masses?

(A) reflection

(B) rarefaction

(D) diffraction

(E) shadowing

195. Approximately what percentage of the ultrasound beam will be transmitted between fat and muscle?

(A) 1%

(B) 10%

(D) 90%

(E) 75%

196. Huygens’ principle is used to describe

(A) attenuation

(B) refraction

(D) wavefront

(E) nonlinear propagation

197. Enhancement may occur posteriorly to structures that are

(A) strong attenuators

(B) weak attenuators

(D) weak refractors

198. Sound attenuation in tissue may be expressed in terms of

(A) half-value layer

(B) millimeters per second

(D) pascals

(E) watts

199. Improper location of an echo may be attributable to

(A) shadowing

(B) Huygens’s principle

(D) propagation speed error

(E) the dead zone

200. The range equation can be used to determine

(A) the number of side lobes

(B) the distance to a reflector

(D) transducer pressure calibration

(E) beam refraction

201. For a specular reflector

(A) the angle of incidence is equal to the angle of reflection

(B) the angle of incidence is greater than the angle of reflection

(D) the angle of incidence is less than the angle of reflection

(E) the surface is smaller than the wavelength

202. Which of the following is determined by the medium?

(A) intensity

(B) period

(D) amplitude

(E) frequency

203. Which of the following is not an acoustic variable?

(A) density

(B) pressure

(D) force

204. Which of the following is an acoustic parameter?

(A) wavelength

(B) frequency

(D) intensity

(E) all of the above

205. What ultrasound method requires two active elements mounted side by side?

(A) pulsed-wave Doppler

(B) harmonic imaging

(D) spectral Doppler

(E) power Doppler

206. The dimensionless index that indicates the likelihood of turbulence to occur is

(A) rayls index

(B) Bernoulli number

(D) Reynold’s number

(E) Rayleigh length

207. Which of the following arranges media in terms of propagation velocity, from lowest to highest?

(A) air, fat, muscle, bone

(B) bone, fat, air, muscle

(D) muscle, air, fat, bone

(E) air, muscle, bone, fat

208. As frequency increases, backscatter

(A) decreases

(B) does not change

(D) none of the above

209. What is the angle at which total reflection occurs called?

(A) critical angle

(B) refractive angle

(D) diffraction angle

(E) angle of incidence

210. The pulse repetition frequency

(A) is the same as the pulse repetition period

(B) is equal to the frame rate

(D) is equal to the number of scan lines per second

211. The units used for the duty factor are

(A) rayls

(B) hertz

(D) unitless

212. The approximate value for the attenuation coefficient for 6 MHz ultrasound in soft tissue is

(A) 3 dB/cm

(B) 3 dB

(D) 6 dB

213. Normal incidence is the term used when the ultrasound beam strikes a boundary between two media at what angle?

(A) parallel

(B) orthogonal

(D) any obtuse angle

214. The amount of energy transmitted and/or reflected at the boundary between two media depends on

(A) acoustic impedance mismatch

(B) the frequency of the beam

(D) the propagation speed of the second medium

215. Which of the following has a higher acoustic impedance coefficient?

(A) solids

(B) liquids

(D) clotted blood

(E) fat

216. According to Snell’s law, the transmission angle is greater than the incidence angle if the propagation speed

(A) of medium 2 is greater than that of medium 1

(B) of medium 1 is greater than that of medium 2

(D) is calculated at 3 dB down

217. A reflected echo is received 39 μs after transmission; what is the depth of the interface?

(A) 3 mm

(B) 0.3 cm

(D) 30 cm

218. The mirror image artifact is commonly seen around which of the following structures?

(A) kidney

(B) pancreas

(D) diaphragm

(E) blood cells

219. What type of artifact is seen with a bright tapering trail of echoes just distal to closely spaced strong reflectors?

(A) edge

(B) mirror image

(D) shadowing

(E) flash

220. Which of the following would be most likely to produce a comet tail artifact?

(A) liver–kidney interface

(B) spleen–kidney interface

(D) cystic mass–liver interface

221. The maximum Doppler shift frequency that can be sampled without aliasing is called

(A) second harmonic limit

(B) dispersion frequency limit

(D) filter limit

222. The frequency bandwidth will typically be increased by

(A) increasing the quality factor

(B) increasing the pulse duration

(D) increasing damping

(E) decreasing damping

223. The likelihood of aliasing in Doppler imaging can be reduced by

(A) increasing the pulse repetition frequency (PRF)

(B) increasing the Doppler angle

(D) reducing the operating frequency

(E) all of the above

224. A reflected echo is received 52 us after transmission; what is the depth of the interface?

(A) 2 cm

(B) 3 cm

(D) 5 cm

225. Generally, ultrasound transducers have

(A) better axial resolution than lateral resolution

(B) better lateral resolution than axial resolution

226. The pulse repetition frequency of an ultrasound unit is typically

(A) 1 Hz

(B) 10 Hz

(D) 1,000 Hz

(E) 10,000 Hz

227. What is the most common artifact in Doppler ultrasound?

(A) flash

(B) aliasing

(D) twinkle

(E) mirror

228. Approximately what percentage of the time is a typical pulsed ultrasound system capable of receiving echoes?

(A) 100%

(B) 99%

(D) 50%

(E) less than 1%

229. If the frequency doubles, what happens to the wavelength?

(A) increases twofold

(B) increases fourfold

(D) decreases fourfold

(E) no change

230. Which of the following does not display a sector format?

(A) linear-sequenced array

(B) electronic-phased array

(D) vector array

231. The equation for measuring acoustic impedance is

232. Which of the following are most commonly used as an active element in ultrasound transducers?

(A) lead zirconate titanate (PZT)

(B) barium lead zirconate (BLZ)

(D) quartz

(E) polyvinylidene fluoride (PVDF)

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

(A) 2 cm

(B) 3 cm

(D) 5 cm

(E) 6 cm

234. What is the total round-trip time in human tissue for reflected echo at a depth of 2 cm?

(A) 6.5 μs

(B) 13 μs

(D) 39 μs

(E) 52 μs

235. The pulse repetition frequency is

(A) pulses emitted per second

(B) time from the beginning of one pulse to the beginning of the next

(D) percentage of time the system is transmitting a pulse

236. Which of the following is the role of the pulser?

(A) voltage generation to drive the transducer

(B) gain adjustment for the receiver

(D) beam steering

237. The type of artifact that produces a reduction in echoes distal to a highly reflective or highly attenuating structure is

(A) enhancement

(B) reverberation

(D) refraction

(E) ring down

238. What is the Nyquist limit if the pulse repetition frequency is 18 kHz?

(A) 2.5 kHz

(B) 3.5 kHz

(D) 9 kHz

(E) 18 kHz

239. Which of the following varies with distance from the transducer?

(A) lateral resolution

(B) frequency

(D) spatial pulse length

240. In Figure 1–59, a period can be described by which number on the following diagram?

(A) #2

(B) #1

(D) #4

FIGURE 1–59.

241. Increasing axial resolution by increasing frequency also results in

(A) decreased near-zone length

(B) decreased penetration

(D) decreased temporal resolution

242. Reflection refers to

(A) the bending of the ultrasound beam as it crosses a boundary

(B) narrowing the ultrasound beam

(D) the scattering of the ultrasound beam in many directions

243. If the transmitted frequency of the transducer is 3.5 MHz. What is the second harmonic frequency?

(A) 1.75 MHz

(B) 3.5 MHz

(D) 2.5 MHz

244. The term bit in computer science denotes

(A) binary digit

(B) pixel

(D) matrix

(E) picture element

245. An 8-bit binary number is referred to as a

(A) byte

(B) baud

(D) voxel

246. What is the purpose of employing an acoustic lens on transducers?

(A) decrease the spatial pulse length

(B) increase the frequency bandwidth

(D) narrowing of the ultrasound beam

247. A needle or membrane hydrophone is used to measure

(A) pressure amplitude

(B) mechanical index

(D) dead zone

248. Viscosity is measured in units of

(A) megahertz

(B) millimeters

(D) pascal

(E) decibels

249. Which one of the following will increase the speed of ultrasound?

(A) increased frequency

(B) decreased frequency

(D) decreased tissue stiffness

250. The resistance to flow offered by a fluid in motion is called

(A) turbulence

(B) eddies

(D) viscosity

251. Autocorrelation is the mathematical process commonly used to detect

(A) aliasing

(B) spectral dispersion

(D) inertia

252. A decrease in dynamic aperture results in

(A) increased temporal resolution

(B) decreased lateral resolution

(D) increased near-zone length

253. Which one of the following would normally have the lowest viscosity?

(A) molasses

(B) coupling gel

(D) water

(E) mineral oil

254. An 8-bit word microcomputer with 128K words of memory can store how many bits of data?

(A) 128

(B) 1,000

(D) 128,000

(E) 1,048,576

255. Harmonics are created

(A) when the focal length is changed

(B) when nonlinear oscillations occur in tissues

(D) when the time gain compensation (TGC) is increased

256. Frequency compounding improves

(A) contrast resolution

(B) penetration depth

(D) lateral resolution

257. What is the unit for acoustic pressure?

(A) pascal

(B) poise

(D) erg

(E) watt

258. What does the horizontal axis (x-axis) on an M-mode display represent?

(A) amplitude

(B) brightness

(D) strength

(E) time

259. Which ultrasound frequency is commonly used in the clinical setting?

(A) 3.5 kHz

(B) 5 kHz

(D) 2.5 kHz

(E) 10 kHz

260. The ratio of the minimum to maximum signal amplitude that can be applied to a device without producing distortion is called

(A) Nyquist ratio

(B) dynamic range

(D) harmonic ratio

261. What does the vertical axis (y-axis) on an M-mode display represent?

(A) amplitude

(B) brightness

(D) strength

(E) time

262. Each binary digit can represent how many different digital memory states?

(A) 1

(B) 2

(D) 8

(E) 10

263. How many digits are utilized in a binary number?

(A) 1

(B) 2

(D) 10

264. What is the binary equivalent of the decimal number 30?

(A) 0110

(B) 1110

(D) 1111

(E) none of the above

265. How many gray levels (echo amplitude levels) can a 4-bit deep digital scan converter store?

(A) 2

(B) 4

(D) 16

(E) 32

266. An ultrasound instrument that could represent 64 shades of gray would require how many bits memory?

(A) 8

(B) 6

(D) 16

(E) 24

267. What are the two categories of cavitation?

(A) turbulent and laminar

(B) stable and transient

(D) analog and digital

268. Which of the following functions are performed by the receiver in the ultrasound machine?

(A) inspection, detection, correction, rejection, depression

(B) randomization, amplification, modulation, rectification, limitation

(D) demodulation, contraction, band limitation, depolarization

269. A large amplitude voltage pulse from the pulser applied to the transducer results in

(A) a long duration pulse from the transducer

(B) a short duration pulse from the transducer

(D) a large amplitude pressure pulse from the transducer

270. Voltage pulses from the pulser to the transducer are also used to

(A) automatically adjust receiver gain

(B) synchronize the receiver for the arrival time determination

(D) determine field of view

271. The five major components of a pulse-echo ultrasound system are

(A) flux capacitor, image memory, transducer, scan arm, amplifier

(B) synchronizer, pulser, receiver, display, power supply

(D) transducer, receiver, image memory, pulser, display

(E) amplification, compression, freeze, demodulation, reject

272. Transducers may be focused by internal focusing and external focusing. These are accomplished by

(A) crystal thickness and/or by adding water path offset

(B) concave transducer elements and/or by using an acoustic lens

(D) adjustment of frequency and/or crystal diameter

273. Which unit is used to specify the Q factor (quality factor)?

(A) pascal

(B) poise

(D) Fresnel

(E) none of the above

Questions 274 through 282: Match each term in Column A with the correct definition in Column B.

COLUMN A

274. acoustic shadow _________

275. acoustic enhancement _______

276. anechoic _______

277. artifact _______

278. echogenic

279. hyperechoic _________

280. hypoechoic _________

281. interface _________

282. sonolucent _________

COLUMN B

(A) without echoes

(B) echoes of lower amplitude than surrounding tissues

(D) an echo that does not correspond to a real structure

(E) reduction in echo amplitudes within a region distal to a strongly attenuating structure

(F) the property of a medium allowing easy passage of sound: low attenuation (echo-free)

(G) an increase in echo amplitudes within a region distal to a weakly attenuating structure

(H) echoes of higher amplitude than the normal surrounding tissues

(I) a structure that produces echoes

283. Which of the following is a commonly used backing material for continuous-wave Doppler transducers?

(A) epoxy resin

(B) cork

(D) tungsten powder

(E) no backing material

284. Which one of the following is not associated with continuous-wave Doppler?

(A) no backing material

(B) no Nyquist limit

(D) no TGC

(E) two transducers

285. The strength of the echo in B-mode ultrasound is displayed as

(A) y-axis deflection

(B) x-axis position

(D) decibels

286. Ultrasound cannot travel in which one of the following?

(A) intravenous pyelogram (IVP) contrast

(B) solid tissue

(D) blood

(E) bone

287. Lambda (λ) represents

(A) period

(B) wavelength

(D) velocity

(E) intensity

288. The time it takes to complete a single cycle is called

(A) period

(B) wavelength

(D) velocity

(E) amplitude

289. A wave vibration at 20 cycles per second has a frequency of

(A) 20 MHz

(B) 20 Hz

(D) 120 kHz

(E) 20,000 MHz

290. A wave vibrating at 1 million cycles per second has a frequency of

(A) 1 GHz

(B) 1 kHz

(D) 100 MHz

(E) 1,000 MHz

291. A damaged active element in a mechanical transducer may result in

(A) a horizontal band of signal dropout at a particular depth

(B) the loss of an entire image

(D) a vertical line of dropout extending from the top to the bottom of the image

Questions 292 through 294: Match the question in Column A with the correct answer in Column B.

COLUMN A

292. Which statement best describes A-mode? _______

293. Which statement best describes B-mode? _______

294. Which statement best describes M-mode? _______

COLUMN B

(A) a graphic presentation with vertical spikes arising from a horizontal baseline; the height of the vertical spikes represents the amplitude of the deflected echo

(B) a two-dimensional image of internal body structures displayed as dots; the brightness of the dots is proportional to the amplitude of the echo; the image is applicable to both real-time and static scanners

(C) one-dimensional presentation of moving structures displayed in a pie-shaped or rectangular image; the image is applicable only to real-time scanners

(D) a graphic presentation of moving structures in a waveform; the display is presented as a group of lines representing the motion of moving interfaces versus time

295. A long dead zone may indicate

(A) a fluid-filled mass

(B) a short spatial pulse length

(D) detached backing material

(E) a high-frequency transducer was used

296. The frame rate in ultrasound is strongly affected by

(A) transducer frequency

(B) focal method

(D) spatial pulse length

(E) imaging depth

297. Doppler signals and velocities cannot be measured at what Doppler angle?

(A) 90°

(B) 30°

(D) 50°

(E) 60°

298. A device used to visualize the dead zone.

(A) radiation force balance

(B) analog-digital converter

(D) Schlieren camera

299. The intensity of the ultrasound beam from a pulsed-echo system

(A) is measured in watts

(B) is constant at all depths

(D) is constant in time

300. Whose principle states that all points on an ultrasound waveform can be considered as point sources for the production of secondary spherical wavelets?

(A) Doppler

(B) Curie

(D) Nyquist

(E) Snell

301. The fraction of time that a pulsed ultrasound system is actually producing ultrasound is called the

(A) duty factor

(B) Curie factor

(D) transmission factor

(E) power

302. Real-time ultrasound transducers can be classified as

(A) annular, sector, linear, and static scanners

(B) sector scanners, vector, and annular

(D) linear sequenced array and vector

303. The speed at which ultrasound propagates within a medium depends primarily on

(A) its frequency

(B) the compressibility of the medium

(D) the thickness of the medium

(E) aperture of the transducer

304. An artifact that results from a pulse that has traveled two or more round-trip distances between the transducer and the interface is called

(A) a multipath

(B) a side lobe

(D) scattering

(E) mirror image

305. The ratio of output of electric power to input electric power is termed

(A) power

(B) intensity

(D) voltage

(E) frequency

306. Multipath artifacts result from

(A) echoes that return directly to the transducer

(B) shotgun pellets

(D) sound wave propagates through a medium at a speed other than soft tissue

(E) small amplitude echoes resulting from electrical interference

307. What type of noise is associated with Doppler shift?

(A) clutter

(B) speckle

(D) harmonics

(E) aliasing

308. To achieve the best possible digital representation of an analog system, the echo signals should undergo

(A) postprocessing

(B) preprocessing

(D) amplification

(E) mechanical impedance

309. Near-zone length may be increased by increasing

(A) wavelength

(B) wavelength and bandwidth

(D) high frequency and large diameter transducer

(E) low frequency and small diameter transducer

Questions 310 through 319: Match each term in Column A with the correct definition in Column B.

COLUMN A

310. density ______

311. propagation _______

312. frequency ______

313. power _______

314. duty factor _______

315. bandwidth _______

316. acoustic impedance _______

317. absorption _______

318. quality factor _______

319. intensity _______

COLUMN B

(A) rate at which work is done

(B) mass divided by volume

(D) number of cycles per unit time

(E) density multiplied by sound propagation speed

(F) range of frequencies contained in the ultrasound pulse

(G) the fraction of time that the ultrasound pulse is on

(H) progression or travel

(I) operating frequency divided by bandwidth

(J) power divided by area

320. Which of the following is a true definition for a highly damped transducer?

(A) increased efficiency, sensitivity, and spatial pulse length

(B) decreased efficiency, sensitivity, and spatial pulse length

(D) decreased efficiency, but increased sensitivity and spatial pulse length

(E) no change in efficiency or sensitivity only in spatial pulse length

321. Gain compensation is necessary due to

(A) reflector motion

(B) gray scale

(D) resolution

(E) none of the above

322. The frequency bandwidth may be determined by which of the following?

(A) spectral analysis

(B) Schlieren system

(D) cathode analysis

(E) refraction

323. Which of the following is not true of power output?

(A) bioeffects concerns

(B) does not affect signal-to-noise ratio

(D) alters patient exposure

(E) should be decreased first if the image is too bright

324. What is the gray-scale resolution for a 5-bit digital instrument that has a dynamic range of 42 dB?

(A) 1.9 dB

(B) 3 dB

(D) 0.07 dB

(E) 13.0 dB

325. If it takes 0.01 seconds for a pulse emitted by the transducer to reach an echo source of soft tissue, what distance must the pulse travel to be recorded?

(A) 1,540 cm

(B) 30.8 m

(D) 1.54 m

(E) 20.8 m

326. An artifact that is produced from interaction of the incident beam with a curved surface and that results in an acoustic shadow is referred to as

(A) a ghost artifact

(B) an edge artifact

(D) a ring down artifact

(E) enhancement artifact

327. An artifact that results from refraction of the ultrasound beam at a muscle-fat interface and that gives rise to double images is called

(A) a split image artifact

(B) an edge artifact

(D) a ring down artifact

(E) speckle artifact

328. An artifact that would least likely produce a pseudo-mass is

(A) a comet tail artifact

(B) a multipath artifact

(D) a slide lobe artifact

(E) ghost artifact

329. Split image artifact is more noticeable in

(A) athletic patients and mesomorphic habitus patients

(B) patients with underdeveloped rectus muscle

(D) all of the above

330. Select the least likely cause or causes for a split image artifact.

(A) abdominal scar

(B) lateral margins of the rectus muscles

(D) refraction of the sound beam at a muscle-fat interface

(E) superficial abdominal skin keloids

331. What is the most likely cause for a beam thickness artifact?

(A) metallic surgical clips

(B) gas bubble

(D) shotgun pellets

(E) abdominal scar

332. Beam thickness artifact is primarily dependent on

(A) position of the patient

(B) gas bubble

(D) gravity

(E) body fat

333. Which of the following is not true for side-lobe artifact?

(A) caused by multiple side lobes of the transducer

(B) direction is different from the main beam

(D) the side-lobe beam is stronger than the primary beam

(E) apodization is used to reduce side lobe artifact

334. Which of the following is least likely to produce an acoustic shadow?

(A) bone interface

(B) metallic surgical clips

(D) gas interface

(E) calcifications

335. The most common type of artifact encountered in patients with shotgun wounds is

(A) comet tail artifact

(B) multipath artifact

(D) side lobe artifact

(E) wound-skin artifact

336. The type of reverberation echo that usually results from a small gas bubble and appears as a high-amplitude echo occurring at regular intervals is called a

(A) multipath artifact

(B) mirror image artifact

(D) ring-down artifact

(E) flash artifact

337. The amount of splitting that occurs in a split image artifact for a given structure

(A) can be calculated using Snell’s law

(B) cannot be calculated because it is an artifact

(D) can be calculated using a 5 MHz transducer with the equation: split (m/s) = Dπ/T

(E) can be calculated using Luez’s law

338. The first vertical deflection on the A-mode that corresponds to the transducer face is called

(A) bistable

(B) side lobe

(D) gain

(E) x-axis

339. The type of real-time system that employs a combination of electronic and mechanical means is called

(A) wobbler sector real-time

(B) rotating wheel real-time

(D) linear-sequenced array

(E) vector array

340. If the amount of acoustic coupling medium is insufficient, what changes could result?

(A) A decrease in amplitude of the returning echo.

(B) A increase in amplitude of the returning echo.

(D) No effect on the image.

(E) An increased penetration into the tissue.

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

(A) spatial compounding

(B) elastography

(D) combined operating mode

(E) clutter

Questions 342 through 344: Each diagram represents modes of operation used in diagnostic ultrasound.

342. Identify the type of mode displayed in the following diagram (Fig. 1–60).

(A) B-mode

(B) A-mode

(D) C-mode

(E) QB-mode

FIGURE 1–60.

343. Identify the type of mode displayed in the following diagram (Fig. 1–61).

(A) B-mode

(B) A-mode

(D) C-mode

(E) QB-mode

FIGURE 1–61.

344. Identify the type of mode displayed in the following diagram (Fig. 1–62).

(A) B-mode

(B) A-mode

(D) C-mode

(E) QB-mode

FIGURE 1–62.

345. The undesired effects of diagnostic ultrasound on human soft tissue as a result of interaction with the ultrasound beam are called

(A) sensitivity effects

(B) biologic effects

(D) radiation poisoning

(E) electromagnetic effect

346. What is the average propagation speed of ultrasound in soft tissue?

(A) 1,540 m/s

(B) 1.54 mm/μs

(D) one mile per second

(E) all of the above

Questions 347 through 350: Identify the regions on the diagram (Fig. 1–63) below by filling in the blanks.

347. slope ______

348. delay ______

349. far gain ______

350. near gain ______

FIGURE 1–63.

Questions 351 through 360: Match each term in Column A with the correct definition in Column B.

COLUMN A

351. attenuation ______

352. elastography ______

353. bit ______

354. cavitation ______

355. coupling medium ______

356. damping ______

357. gray scale ______

358. matching layer ______

359. pixel ______

360. static imaging ______

COLUMN B

(A) picture element

(B) the production and behavior of microbubbles within a medium

(D) a liquid placed between the transducer and the skin

(E) the number of intensity levels between black and white

(F) imaging technique to assess tissue stiffness

(G) binary digit

(H) a method of reducing pulse duration by electrical or mechanical means

(I) single-frame imaging

(J) plastic material placed in front of the transducer face to reduce the reflection at the transducer surface

361. The intensity of ultrasound is measured in

(A) kg/m³

(B) N/m²

(D) W/cm²

(E) MHz

362. The imaging technique that allows previous hidden structures beneath highly attenuating objects to become visible is called

(A) spatial compounding

(B) elastography

(D) combined operating mode

(E) clutter

363. The acronym SPTA denotes

(A) static probe transmission amplitude

(B) static probe transmission absorption

(D) sound propagation temperature artifact

Questions 364 through 370: Match the quantity in Column A with the correct unit in Column B.

COLUMN A

364. density ______

365. speed ______

366. frequency ______

367. work ______

368. intensity ______

369. wavelength ______

370. attenuation ______

COLUMN B

(A) W/cm²

(B) kg/m³

(D) m/s

(E) Joule (J)

(F) Hz

(G) dB

371. The general range of intensities in diagnostic ultrasound is

(A) 0.5 W/cm²–2.0 W/cm² SPTA

(B) 0.002 W/cm²–0.5 W/cm² SPTA

(D) 100 W/cm² SPTA to 1,000 W/cm² SPTA

(E) the general range of intensities in diagnostic ultrasound is unknown

372. The general range of intensities in therapeutic ultrasound is

(A) 0.5 W/cm²–2.0 W/cm² SPTA

(B) 0.002 W/cm²–0.5 W/cm² SPTA

(D) 20.5 W/cm²–30.0 W/cm² SPTA

(E) the general range of intensities in therapeutic ultrasound is unknown

373. Which of the following characteristics does not apply to diagnostic ultrasound at normal diagnostic intensity levels?

(A) noninvasive

(B) atraumatic

(D) nontoxic

(E) absorption

374. What is the most common result of high-intensity ultrasound?

(A) cavitation

(B) brain damage

(D) heat

(E) mitosis of cells

375. In the study of bioeffects, what does cavitation denote?

(A) production and behavior of gas bubbles

(B) necrosis

(D) chromosome breakage

(E) mitosis of cells

376. What are the two types of cavitation?

(A) silent and noisy

(B) micro and macro

(D) stable and transient

(E) heat and absorption

377. An instrument used to detect frequency shift is called

(A) Doppler

(B) real-time

(D) static scanner

(E) hydrophone

378. Specular reflections

(A) occur when the interface is larger than the wavelength

(B) occur when the interface is smaller than the wavelength

(D) are not dependent on the angle of incidence

(E) occur at irregular surface interfaces

379. Nonspecular reflections

(A) occur when the interface is larger than the wavelength

(B) occur when the interface is smaller than the wavelength

(D) are beam-angle dependent

(E) occur at a smooth boundary

380. The acronym SATA denotes

(A) static amplitude transmission average

(B) spatial average temporal average

(D) sound attenuation transmission average

(E) safety accuracy in tissue acoustic

381. The acronym SPPA denotes

(A) static probe power average

(B) static probe transmission absorption

(D) sound propagation performance average

(E) safety parameters and protocols for acoustics

382. Which mode is not applicable to a Doppler instrument?

(A) A-mode

(B) pulsed

(D) audible

(E) duplex

383. Which of the following transducers would be most useful for imaging superficial structures?

(A) 5 MHz, short-focus

(B) 3 MHz, long-focus

(D) 2.5 MHz, short-focus

(E) 3.5 MHz, short-focus

384. Which of the following transducers would be most useful for good penetration on an obese patient?

(A) 5 MHz, short-focus

(B) 3 MHz, long-focus

(D) 2.5 MHz, short-focus

(E) 10 MHz, long-focus

385. The digital memory represents a picture element called a

(A) pixel

(B) electrons

(D) matrix

(E) phosphors

386. How many shades of gray can the human eye distinguish?

(A) about 16 shades

(B) between 150 and 250 shades

(D) more than 1,000 shades

(E) 256 shades

387. The most recent digital storage employs what size memory?

(A) 512 × 512 × 8-bit deep and 256 shades

(B) 64 × 64 × 2-bit deep

(D) 16 × 16 × 2-bit deep

(E) 30 × 30 × 6-bit deep and 16 shades

388. Which of the following is a disadvantage of pulsed-wave (PW) Doppler relative to continuous-wave (CW) Doppler?

(A) It is unidirectional.

(B) The Doppler shift depends on frequency.

(D) It does not provide in-depth information.

389. Which of the following does not utilize gain?

(A) duplex imaging

(B) real-time system

(D) color Doppler

(E) all of the above

390. What is the effect of ultrasound absorption on tissues at normal intensity levels?

(A) dissipation of heat by conduction

(B) significant temperature elevations

(D) necrosis

(E) cavitation

391. Which of the following is not an advantage of continuous-wave Doppler?

(A) ability to measure very high velocities

(B) the absence of aliasing

(D) ability to use high frequency

(E) range ambiguity

392. Turbulent flow is most likely to occur in which one of the following situations?

(A) high velocities and acute anemia

(B) small diameter and high viscosity

(D) large diameter, low velocity, and polycythemia

(E) large diameter, low velocity, and low viscosity

393. Which one of the following can be used to decrease the likelihood of aliasing on aspectral analysis?

(A) using higher transducer frequency

(B) decreasing the pulse repetition frequency (PRF)

(D) lowering the baseline

394. Temporal resolution is decreased with all of the following except

(A) wide sector

(B) shallow imaging

(D) increased 2D depth

(E) lower frame rate

395. Which one of the following most likely is a contributor to aliasing?

(A) high frequency

(B) continuous Doppler

(D) slow blood velocity

(E) lower frequency

396. Digital memory can be visualized as

(A) squares on a checkerboard

(B) a transducer

(D) a hydrophone

(E) a beam of light

397. A region that is anechoic is displayed as

(A) echo-free

(B) echogenic

(D) hypoechoic

(E) isoechoic

398. A region that is hyperechoic is

(A) anechoic

(B) echogenic

(D) transonic

(E) isoechoic

399. Which of the loll owing cannot be measured by a hydrophone?

(A) acoustic pressure

(B) spatial pulse length

(D) intensity

(E) period

400. The hydrophone is made up of

(A) algae inhibitor and alcohol to mimic soft tissue speed

(B) small transducer elements

(D) gelatin and vinyl chloride

(E) stainless steel pins

401. Bioeffects at medium intensity levels on laboratory animals have resulted in

(A) cancer

(B) death

(D) no effects

(E) tissue necrosis

402. Which of the following is the least likely cause for attenuation?

(A) absorption

(B) reflection

(D) scattering

(E) bone

403. Absorption refers to

(A) bending of the sound beam crossing a boundary

(B) conversion of sound to heat

(D) redirection of the sound beam in several directions

(E) conversion of heat to sound

404. Diffraction refers to

(A) spreading-out of the ultrasound beam

(B) conversion of sound to heat

(D) bending of the sound beam crossing a boundary

(E) the narrowing of the sound beam

405. Scattering refers to

(A) bending the sound beam crossing a boundary

(B) conversion of sound to heat

(D) redirection of the sound beam in several directions

(E) all of the above

406. The method for sterilizing transducers is

(A) heat sterilization

(B) steam

(D) autoclave

(E) ethylene oxide

407. An example of an acoustic window is

(A) liver interface

(B) rib interface

(D) tissue/bone interface

(E) none of the above

408. The binary number 1010 equals the decimal number

(A) 10

(B) 11

(D) 200

(E) 101

409. What are the lowest intensity measurements that are used in diagnostic ultrasound?

(A) SPPA

(B) SATP

(D) SAPA

(E) SATA

410. What is the intensity that is used in diagnostic ultrasound to measure the potential biological effects in mammalian tissue?

(A) SATA

(B) SPTA

(D) SAPA

(E) SATP

411. Which is the recommended orientation for a transverse scan?

(A) all transverse scans should be viewed from the patient’s feet.

(B) all transverse scans should be viewed from the patient’s head.

(D) all transverse scans should be viewed lateral from the patient’s left side.

(E) there is no standard image orientation for transverse scans.

412. What is the recommended orientation for longitudinal scans?

(A) the patient’s head to the right of the image and feet to the left of the image

(B) the patient’s head to the left of the image and feet to the right of the image

(D) scans should be viewed from the patient’s feet

(E) there is no standard image orientation for longitudinal scans

413. Demodulation is a function performed by which of the following?

(A) pulser

(B) amplifier

(D) transmitter

(E) transducer

414. Which of the following statements about ultrasound waves is not true?

(A) ultrasound waves are mechanical vibrating energy.

(B) ultrasound waves can be polarized.

(D) ultrasound waves cannot travel in a vacuum.

(E) ultrasound waves are longitudinal waves.

415. The transducer crystal most likely to be employed in high-frequency work, above 18 MHz, is

(A) lithium sulfate

(B) lead zirconate titanate

(D) quartz

(E) barium titanate

416. Lead zirconate titanate has which of the following advantages over other ceramic materials?

(A) easy to shape

(B) effective at low voltage

(D) greater temperature stability

(E) all of the above

417. All of the following statements about a linear-phased transducer is true except?

(A) produces a sector image

(B) the sound beam is focused electronically

(D) elements are fired in successive groups

(E) all scan lines are perpendicular to the transducer face

418. How many shades of gray can be displayed using a scan converter with 8 bits per memory element?

(A) 16

(B) 30

(D) 256

(E) 525

419. The highest intensity measurements used in diagnostic ultrasound denoted by which of the following?

(A) SATA

(B) SATP

(D) SPTP

(E) SPPA

420. What is the difference between real-time ultrasound and x-ray fluoroscopy?

(A) ultrasound does not always require contrast media.

(B) fluoroscopy has potential biologic effects; whereas, ultrasound has no known biologic effects at normal intensity level.

(D) ultrasound cannot travel in a vacuum and x-rays can travel in a vacuum.

(E) all of the above.

421. Which of the following contrast media used in x-rays can obscure the propagation of ultrasound?

(A) barium sulfate (BaSO₄) for upper GI examination

(B) hypaque for IVP examination

(D) Telepaque for oral cholecystogram

(E) all of the above

Questions 422 through 430: Match each term in Column A with the correct definition in Column B.

COLUMN A

422. acoustic lens ______

423. pixel ______

424. sector ______

425. acousto-optical converter ______

426. side lobe ______

427. wavefront ______

428. rayl ______

429. Snell’s law ______

430. Doppler effect ______

COLUMN B

(A) unit of impedance

(B) the portion of the sound beam outside of the main beam

(D) pie shaped

(E) a change in frequency as a result of reflector motion between the transducer and the reflector

(F) a device that changes sound waves into visible light patterns

(G) the ratio between the angle of incidence and the refraction

(H) imaginary surface passing through particles of the same vibration as an ultrasound wave

(I) a device used to focus sound beams

431. Lateral resolution is equal to

(A) the wavelength

(B) the beam diameter

(D) the wave number

(E) damping material

432. Which of the following materials is not used to make acoustic lenses?

(A) aluminum

(B) Perspex (acrylic plastic)

(D) ethylene oxide

(E) all of the above

433. Ultrasound beams can be focused and defocused with the use of

(A) a concave or convex mirror

(B) acoustic lenses

(D) ultrasound beam cannot be focused; only light can be focused

(E) all of the above

434. What is the normal range of wavelength in medical application?

(A) 0.77–0.15 mm

(B) 1.5–5.4 mm

(D) 5.5–15 mm

(E) 0.1–1.0 mm

435. Which of the following cannot be distinguished on diagnostic ultrasound?

(A) tissue

(B) solid mass

(D) male and female genitalia

(E) nerve

436. Density is defined as

(A) unit of impedance

(B) force divided by area

(D) mass per unit volume

(E) unit of pressure

437. Ultrasound absorption is directly proportional to

(A) viscosity

(B) frequency

(D) increased collagen content

(E) all of the above

438. The confirmed bioeffect(s) on pregnant women with the use of real-time diagnostic instruments is (are)

(A) brain damage

(B) fetal developmental anomalies

(D) no known effect

(E) lung hemorrhage

439. The confirmed bioeffects on pregnant mice exposed to continuous-wave ultrasound in a laboratory setting have resulted in

(A) cancer

(B) death

(D) necrotic tissue

(E) no known effect

440. Which of the following combinations of frequency and intensity would most likely result in cavitation?

(A) high frequency and low intensity

(B) low frequency and high intensity

(D) low frequency and low intensity

(E) intensity has no effect on cavitation

Questions 441 through 448: Match each term in Column A with the correct definition in Column B.

COLUMN A

441. in vivo _______

442. in vitro _______

443. spectral analysis _______

444. viscoelasticity _______

445. rejection _______

446. relaxation _______

447. real cell stasis _______

448. acoustic power _______

COLUMN B

(A) an in vivo phenomenon characterized by erythrocytes within small vessels stopping the flow and collecting in the low pressure regions of the standing wave field

(B) elimination of small amplitude echo

(D) energy transported per unit time

(E) tissue cultures in a test tube

(F) a method of analyzing a waveform

(G) the property of a medium characterized by energy distortion in the medium and irreversibly converted to heat

(H) living human tissue

449. Which of the following statements about bioeffects is (are) unconfirmed?

(A) ultrasound exposure in humans is accumulative.

(B) most harmful bioeffects that occurred in experimental conditions have been confirmed in humans in a clinical setting.

(C) intensity, frequency, and exposure time used on experimental animals were compatible to those used in a clinical setting.

(D) continuous wave used in experimental studies gives the same tissue exposure as pulsed ultrasound used in a clinical setting.

(E) the exposure of pregnant women to high intensity levels resulted in growth retardation of their offspring.

(F) all of the above are false or unconfirmed.

450. The number of known human injuries resulting from diagnostic medical ultrasound exposure is

(A) 2,500 in England

(B) 115 in the United States

(D) 5 cases in last 10 years

(E) no exposure injuries in humans have been reported

451. What is the distinction between real-time scans and B-scans?

(A) no distinction; real-time scans are B-scans.

(B) Real-time scans display gray-scale images, whereas B-scans display bistable images.

(D) B-scans are specific for static scanners; real-time scans are not.

452. Transonic regions are always

(A) echo-free

(B) anechoic

(D) uninhibited to propagation

(E) isoechoic

453. Which of the following is not related to real-time?

(A) A-mode

(B) static imaging

(D) M-mode

(E) color Doppler

454. Which of the following is not a component of the time gain compensation (TGC) curve?

(A) gray scale

(B) far gain

(D) delay

(E) slope

455. The range of pulse repetition frequencies used in diagnostic ultrasound is

(A) 4–15 kHz

(B) 2.5–10 MHz

(D) 10–15 MHz

(E) 0.5–4 MHz

456. The spatial pulse length is defined as the product of the _______ multiplied by the number of _______ in a pulse.

(A) cycles; frequency

(B) frequency; velocity

(D) frequency; wavelength

(E) amplitude; distance

457. Which of the following is (are) one-dimensional?

(A) B-mode and A-mode

(B) A-mode and M-mode

(D) static imaging

(E) color Doppler

458. When multiple images are created over time and organized to create one image, this is known as which of the following?

(A) harmonic imaging

(B) spatial compounding

(D) frequency compounding

(E) fast Fourier transform (FFT)

459. Which imaging modality is audible?

(A) x-ray

(B) ultrasound

(D) computed tomography (CT)

(E) harmonic imaging

460. Which mode requires two crystals: one for transmitting and one for receiving?

(A) A-mode

(B) M-mode

(D) pulse-echo mode

(E) power Doppler

Question 461 through 464: Fill in the blanks by correlating with the letters in Fig. 1–64

461. (A) _________________________________________

462. (B) _________________________________________

463. (C) _________________________________________

464. (D) _________________________________________

FIGURE 1–64.

465. The normal range of intensities used in Doppler instruments is

(A) 0.2–400 W/cm²

(B) 0.2–400 mW/cm²

(D) 800–900 mW/cm²

(E) 2.0–100 W/cm²

466. If the media boundary is moving toward the source, the reflected sound wave will have

(A) a higher frequency than the incident frequency

(B) a lower frequency than the incident frequency

(D) be delayed

(E) aliasing

467. If the media boundary is moving away from the source, this will result in

(A) a higher frequency than the incident frequency

(B) a lower frequency than the incident frequency

(D) aliasing

(E) delayed sound

468. A Doppler instrument that can distinguish between positive and negative shifts is called

(A) bistable

(B) a modulator-demodulator

(D) a polarized shifter

(E) Nyquist limit

469. Which statement about Doppler application is not true?

(A) Doppler color has slower velocities that are represented by lighter hues

(B) Doppler is within the audible range

(D) Doppler can display an image

(E) Doppler cosine of 90° is zero

Questions 470 through 474: Match the time gain compensation (TGC) controls in Column A with the control functions in Column B.

COLUMN A

470. near gain.

471. far gain ________

472. slope ________

473. delay ________

474. knee ________

COLUMN B

(A) control used to suppress or increase echoes in the far field

(B) control used to suppress or increase echoes in the near field

(D) control the upward incline of the TGC, used to display an even texture

(E) controls the point where the slope ends

475. The range of frequencies contained in an ultrasound pulse is called

(A) intensity

(B) bandwidth

(D) spatial pulse length

(E) duty factor

476. Which quantity is unitless?

(A) Q-factor

(B) volume

(D) force

(E) period

477. Which of the following would be most likely to cause acoustic enhancement?

(A) a solid mass

(B) a urine-filled bladder

(D) a gallstone

(E) echogenic fluid

478. Which of the following would be most likely to cause acoustic shadowing?

(A) gallbladder

(B) a fluid-filled mass

(D) urinary bladder

(E) echogenic fluid

479. Which of the following is not related to the sonographic description of blood flow?

(A) laminar

(B) pooling

(D) plug

(E) disturbed

480. The greatest Doppler angle is achieved

(A) when the beam strikes a vessel at a sharp right angle

(B) when the beam strikes a vessel perpendicular

(D) when the beam strikes a vessel at a 70° angle

(E) when the beam strikes a vessel at an orthogonal angle

481. If the power output of an amplifier is 100 times the power at the input, what is the gain?

(A) 10 dB

(B) 20 dB

(D) 40 dB

(E) 60 dB

482. Which control is used to minimize the effects of attenuation?

(A) reject

(B) field-of-view

(D) time gain compensation

(E) depth

483. When an ultrasound beam passes obliquely across the boundary between two materials, what will occur if there is a difference in acoustic impedance in the two materials?

(A) reflection, impedance

(B) reflection, density

(D) refraction, propagation speed

(E) no change

484. A decreased pulse duration leads to which of the following?

(A) better axial resolution

(B) decreased spatial resolution

(D) better lateral resolution

(E) none of the above

485. What is the reflected intensity from a boundary between two materials if the incident intensity is 1 mW/cm² and the impedances are 25 and 75?

(A) 0.25 mW/cm²

(B) 0.33 mW/cm²

(D) l.00 mW/cm²

(E) l00 mW/cm²

486. The near-zone length of an unfocused transducer depends on

(A) frequency and thickness

(B) frequency and diameter

(D) diameter and field of view

(E) Time gain compensation

487. The frequency of a transducer depends primarily on which of the following?

(A) overall gain

(B) the speed of ultrasound

(D) the element thickness

(E) near and far gain

488. An ultrasound beam with a normal incident will experience no

(A) attenuation

(B) refraction

(D) absorption

(E) demodulation

489. What is the average speed of propagation of ultrasound in soft tissue?

(A) 1,540 ft/s

(B) 1.54 dB/cm

(D) 1,540 mW/cm²

(E) one mile per minute

490. The duty factor for a system with a pulse duration (PD) of 5 μs and a pulse repetition period (PRP) of 500 us is

(A) 0.1%

(B) 0.5%

(D) 10.0%

(E) 100%

491. What increases the acoustic energy that a patient receives?

(A) high frequency

(B) wavelength

(D) examination time

492. Frequency is a significant factor in

(A) propagation speed

(B) tissue compressibility

(D) transducer diameter

(E) all of the above

493. In a pulse-echo system, a 3.5 MHz beam of 2 cm of tissue will be attenuated by

(A) 3.5 dB/cm

(B) 7.0 dB/cm

(D) 7.0 dB

(E) 30.0 dB

494. The characteristic acoustic impedance of a material is equal to the product of the material density and

(A) path length

(B) wavelength

(D) propagation speed

(E) power

495. In what area of a stenotic blood vessel does the maximum velocity of blood occur?

(A) within the stenosis

(B) before the stenosis

(D) before and after the stenosis

(E) one cm after the stenosis

496. For normal incidence, if the intensity reflection coefficient is 30%, the intensity transmission coefficient will be

(A) 15%

(B) 30%

(D) 70%

(E) 100%

497. Turbulent flow is possible when blood flow exceeds what Reynolds number?

(A) 100

(B) 200

(D) 2,000

(E) 10

498. The range equation relates

(A) frequency, velocity, and wavelength

(B) frequency, velocity, and time

(D) distance, frequency, and time

(E) incidence, reflection, and refraction

499. Which of the following predicts the onset of turbulent flow?

(A) dosimetry

(B) acoustic pressure

(D) wall thump

(E) flow detector

500. The Doppler shift frequency is zero when the angle between the receiving transducer and the flow direction is

(A) 0°

(B) 45°

(D) 180°

(E) 190°

501. Turbulence flow occurs at what area of a stenotic blood vessel?

(A) within the stenosis

(B) before the stenosis

(D) before and after the stenosis

(E) all of the above

502. The dynamic range of a pulse-echo ultrasound system is defined as

(A) the ratio of the maximum to the minimum intensity that can be processed

(B) the range of propagation speeds

(D) the difference between the transmitted and the received ultrasound frequency

(E) none of the above

503. The thermal paper printer is not working, what is the first step?

(A) call the manufacturer for service

(B) check for a paper jam

(D) call the ultrasound supervisor

(E) call environmental services

504. The time gain or depth gain compensation control

(A) compensates for attenuation effects

(B) compensates for increased patient scan time

(D) compensates for video-image drifts

(E) all of the above

505. A digital scan converter is essentially a

(A) radio receiver

(B) video monitor

(D) computer memory

(E) optical media

506. An increase in peak rarefactional pressure could result in which of the following?

(A) increased thermal index

(B) hypothermia of biological tissue

(D) inertial cavitation

(E) cancer

507. Acoustic enhancement can be observed when scanning

(A) highly attenuating structures

(B) weakly attenuating structures

(D) structures with large speed differences

(E) surgical clips

508. Ultrasound depth penetration is inversely related to

(A) period

(B) propagation speed

(D) frequency

(E) aperture

509. Lateral resolution

(A) is affected by the beam diameter

(B) is affected by aperture size and acoustic lens

(D) is improved with increased frequency

(E) all of the above

510. If the lines per degree in a mechanical sector scanner remain constant, a decreased sector angle can result in

(A) decreased resolution

(B) increased frame rate

(D) increased resolution

(E) no change

511. What letter represents a group of nylon lines used to evaluate horizontal distance accuracy in this tissue-equivalent phantom (Fig. 1–65)?

(A) line A

(B) line B

(D) line D

(E) line E

FIGURE 1–65.

512. What letter represents a group of nylon lines used to evaluate range accuracy in this tissue-equivalent phantom (Fig. 1–65)?

(A) line A

(B) line B

(D) line D

(E) line E

513. The advantages of continuous wave (CW) include all of the following except

(A) ability to measure very high velocities

(B) ability to use high frequencies

(D) range ambiguity

(E) no Nyquist limit

514. If the gain of an amplifier is 18 dB, what will the new gain setting be if the gain setting is reduced by one-half?

(A) 9 dB

(B) 36 dB

(D) 0.5 dB

(E) 18 dB

515. Decreasing the pulse repetition period

(A) decreases spatial resolution

(B) decreases axial resolution

(D) increases the maximum depth imaged

(E) none of the above

516. The AIUM 100-mm test object is used to evaluate all of the following except

(A) registration

(B) dead zone

(D) azimuthal resolution

(E) attenuation

517. A 3.5 MHz transducer is used on a patient with the ultrasound wave propagating the various tissues listed below. Which one will have the longest wavelength?

(A) muscle

(B) blood

(D) fat

(E) lungs

518. What type of resolution is degraded in the presence of grating lobes and side lobes?

(A) lateral

(B) axial

(D) range

(E) contrast

519. Spatial compounding improves the quality of the image in several ways except

(A) reducing the amount of reverberation and shadowing in the image

(B) reduced clutter artifacts

(D) creating multiple images in a single angle

520. A 7.5 MHz transducer is used on a patient with the ultrasound wave propagating various tissues listed below. Which one will have the shortest wavelength?

(A) muscle

(B) blood

(D) fat

(E) lungs

521. The ability of a system to detect low-amplitude echoes accurately is referred to as

(A) resolution

(B) sensitivity

(D) dynamic accuracy

(E) registration accuracy

522. The primary mechanisms whereby ultrasound can produce biologic effects are

(A) thermal and cavitation

(B) absorption and reflection

(D) photon energies and ultraviolet

(E) gamma rays and molecular electron

523. The near-zone length of a transducer depends on

(A) propagation speed and frequency

(B) frequency and transducer diameter

(D) magnification

(E) time gain compensation

524. The AIUM Committee on Biological Effects in 1991 stated what biologic effects with the use of ultrasound intensities below SPTA 100 mW/cm²?

(A) has small amount reported cases of cancer of the fetal kidneys

(B) has no confirmed effects in mammalian

(D) mammalian effects was minimal

(E) minimal amount of neurological defects in sonographers after 20 years

525. The intensity of a focused beam is generally

(A) constant

(B) highest at the transducer surface

(D) lowest at the transducer surface

(E) lowest at the focal zone

526. The wavelength of a 5 MHz wave passing through soft tissue is approximately

(A) 0.1 mm

(B) 0.3 mm

(D) 1.0 mm

(E) 3.0 mm

527. An echo that has undergone an attenuation of 3 dB will have an intensity that is ____ than its initial intensity.

(A) three times smaller

(B) three times larger

(D) two times larger

(E) one time larger

528. Linear array transducers are commonly called

(A) vector

(B) phased

(D) annular

(E) sequential

529. A 5 MHz transducer used in a pulse-echo system will generally produce

(A) a wide band of frequencies centered at 5 MHz

(B) frequencies only at 5 MHz

(D) a wide band of frequencies above 5 MHz

(E) a narrow band of frequencies centered at 5 MHz

530. The transducer _______ determines its _______.

(A) diameter; intensity

(B) damping; lateral resolution

(D) thickness; resonance frequency

(E) width; power

531. The axial resolution of a transducer can be improved with _______ but at the expense of_______.

(A) increased damping; sensitivity

(B) frequency; lateral resolution

(D) focusing; lateral resolution

(E) beam width; lateral resolution

532. A material that changes its dimensions when an electric field is applied is called which of the following?

(A) piezoelectric

(B) acoustic-optics

(D) acoustic insulator

(E) damping element

533. The process of making the impedance values on either side of a boundary as close as possible to reduce reflections is known as which of the following?

(A) damping

(B) refracting

(D) compensating

(E) acoustic insulator

534. Which of the following data medium has the largest storage capacity used in diagnostic ultrasound?

(A) flash drive

(B) CD

(D) DVD

(E) RAID

535. Shadowing occurs with

(A) highly attenuating structures

(B) large changes in propagation speed

(D) weak reflectors

(E) highly propagated structures

536. Reverberation artifacts

(A) occur most often at high frequencies

(B) occur with multiple strong reflecting structures

(D) cannot occur in color Doppler systems

(E) are more frequently seen in solid masses

537. A transducer with a large bandwidth is likely to have

(A) good axial resolution

(B) a large ring-down time

(D) a high Q factor

(E) poor axial resolution

538. The region of the ultrasound beam from the focus to beam diversion is called which of the following?

(A) Fraunhofer zone

(B) Fresnel zone

(D) divergence zone

(E) acoustic focus

539. Refraction will not occur at an interface

(A) when high frequencies are used

(B) if the acoustic impedances are equal

(D) with normal incidence of the ultrasound beam

(E) when the propagation speed of the two media is the same

540. Acoustic power output is determined primarily by

(A) the diameter of the transducer

(B) the thickness of the transducer

(D) focusing

(E) time gain compensation

541. Specular reflections occur when

(A) the reflecting object is small with respect to the wavelength

(B) the reflecting surface is large and smooth with respect to the wavelength

(D) the angle of incidence and angle of reflection are unequal

(E) diffuse reflection creates backscatter

542. The angle at which an ultrasound beam is bent as it passes through a boundary between two different materials is described mathematically by which of the following?

(A) Huygen’s principle

(B) Curie’s principle

(D) Nyquist limit

(E) Rayleigh principle

543. What type of transducer is composed of multiple ring-shaped elements?

(A) annular

(B) linear sequential arrays

(D) phased array

(E) vector

544. The percentage of an ultrasound beam reflected at an interface between gas and soft tissue is approximately

(A) 90–100%

(B) 70–80%

(D) 10–25%

(E) >1%

545. The percentage of an ultrasound beam reflected at an interface between fat and muscle is approximately

(A) 90–100%

(B) 70–80%

(D) 15–25%

(E) 1–10%

546. Which of the following is a reason to use an acoustic standoff?

(A) to reduce tissue attenuation

(B) to move the focal zone closer to the skin surface

(D) to move the focal zone deeper in the body structure

(E) to visualize deep image structures

547. Ultrasound waves in tissue are referred to as

(A) shear waves

(B) transverse waves

(D) longitudinal compression waves

(E) ultraviolet waves

548. High-frequency transducers have

(A) shorter wavelengths and less penetration

(B) longer wavelengths and greater penetration

(D) longer wavelengths and less penetration

549. When the piezoelectric crystal continues to vibrate after the initial voltage pulse, this is referred to as

(A) ring-down time

(B) pulse delay

(D) overdamping

(E) depolarization

550. Annular phased arrays, unlike linear phased arrays,

(A) can be dynamically focused

(B) electronically focus in two dimensions rather than one

(D) can achieve high frame rates

(E) electronically focus in one dimension

551. Which group is arranged in the correct order of increasing propagation speed?

(A) gas, bone, muscle

(B) bone, muscle, gas

(D) muscle, bone, gas

(E) bone, tendon, muscle, blood, lungs

552. The lower useful range of diagnostic ultrasound is determined primarily by _______, whereas, the upper useful range is determined by _______.

(A) resolution; penetration

(B) scattering; propagation speed

(D) scattering; resolution

553. Convert the number 125,000,000,000 to engineering notation.

(A) 125 × 10^–11

(B) 1.25 × 10¹¹

(D) 125 × 10⁹

(E) 125 × 10⁶

554. Which of the following is true?

(A) SPTA is always equal to or greater than SPTP

(B) SPTP is always equal to or greater than SPTA

(D) SPTA is always equal to or greater than SATP

555. A beam-intensity profile is often mapped with

(A) dosimetry

(B) acousto-optics

(D) AIUM test object

(E) calorimeter

556. If the direction of flow is perpendicular to the sound beam, what is the velocity and cosine?

(A) velocity is 1 and the cosine is 1

(B) velocity is 0.87 and the cosine is 0.87

(D) velocity is –1.0 and the cosine is –1.0

(E) velocity is zero and the cosine is zero

557. The technique of passing an ultrasound beam through water so that compression and rarefaction of the water molecules allow the beam pattern to be measured is referred to as the

(A) Doppler method

(B) Schlieren method

(D) water-density method

(E) acousto-optics

558. Pulse duration is the _______ for a pulse to occur.

(A) space

(B) range

(D) time (D) distance

559. A 10 MHz Doppler transducer is used with a PRF of 2,000 Hz with an image depth of 12 cm. What is the Nyquist frequency?

(A) 20 Hz

(B) 24 dB

(D) 1 dB

(E) 2,000 Hz

560. What is the unit of measure of SPTA?

(A) dB

(B) W/cm²

(D) Hz

(E) MHz

561. The piezoelectric properties of a transducer will be lost if the crystal is heated above the

(A) crystal point

(B) dynamic range

(D) dead zone

(E) Nyquist limit

562. If the amplitude of a wave is increased threefold, the intensity will

(A) decrease threefold

(B) increase threefold

(D) increase sixfold

(E) intensity does not change with the increase in amplitude

563. Which of the following is used to improve the signal-to-noise ratio?

(A) output power

(B) near gain

(D) receiver gain

564. If the frequency is increased, the _______ will be _______.

(A) velocity; increased

(B) attenuation; decreased

(D) velocity; unchanged

565. Beam steering is achieved in a linear phased array by

(A) mechanical motion

(B) electronic time-delay pulsing

(D) dynamic focusing

566. Dynamic focusing

(A) is made possible by array-based systems

(B) is made possible by acoustic lens

(D) is often used in single-element systems

567. Adjusting the overall gain will increase or decrease the brightness of the image due to which of the following?

(A) amplification of the receiver voltage

(B) magnification

(D) temperature of the tissue

(E) kinetic energy

568. Sound will travel ____ in 1 μs in soft tissue.

(A) 1,540 m

(B) 1.54 cm

(D) 0.75 mm

(E) one mile per minute

569. The arrow in Fig. 1–66 points to which of the following?

(A) ring-down artifact

(B) mirror image artifact

(D) ghost artifact

(E) distal acoustic shadow

FIGURE 1–66.

570. In the image in Fig. 1–67, that represents a tissue-equivalent phantom, what do the small open arrowheads point to?

(A) rods for measuring dead zone

(B) parallel rods used for horizontal calibration

(D) rods used for measuring registration

(E) simulated cystic mass

FIGURE 1–67.

571. In the image in Fig. 1–67, that represents a tissue-equivalent phantom, what does the curved open arrow point to?

(A) a dead zone

(B) a simulated solid lesion

(D) a side lobe artifact

(E) a simulated cystic mass

572. In the image in Fig. 1–67, that represents a tissue-equivalent phantom, what does the solid black arrow point to?

(A) a ghost artifact

(B) a dead zone

(D) a side lobe artifact

(E) a simulated solid mass

573. What determines the frequency of the transducer?

(A) beam shape

(B) aperture

(D) element thickness

(E) time gain compensation

574. At the present time, most ultrasound contrast agents are based upon

(A) radiopaque media

(B) higher viscosity liquids

(D) gas-filled microbubbles

(E) barium sulfate

575. Microspheres filled with which of the following materials are currently used as an ultrasound contrast agent?

(A) xenon

(B) perfluorocarbon

(D) gadolinium

(E) barium sulfate

576. As the pulse repetition frequency is increased, what is the potential effect?

(A) depth of view increases

(B) depth of view decreases

(D) poor spatial resolution

(E) decreased frame rate

577. Acoustic clutter and ghosting artifact can be eliminated with

(A) magnification

(B) time gain compensation

(D) autocorrelation

(E) wall filter

578. What type of noise arises from small amplitude sound waves that interfere with each other?

(A) clutter

(B) speckle

(D) signal processing

(E) spurious reflections

579. Duplex imaging combines gray scale with Doppler and can appear as

(A) M-mode and spectrum

(B) B-mode and spectrum

(D) all of the above

580. Doppler color-flow imaging produces an image composed of

(A) tissue echoes in gray scale and blood echoes in color

(B) moving soft tissue echoes in gray scale and blood motion in color

(D) stationary tissues in gray scale and stationary blood in color

581. Color Doppler imaging is a term used to describe

(A) a form of color-flow imaging

(B) a form of magnetic resonance imaging

(D) a form of detecting flow with lasers

582. The Doppler effect occurs

(A) only to waves traveling more than 1,000 m/s

(B) only to ultrasound waves with intensities greater than 500 mW/cm², SPTA

(D) in ultrasound, but only when the targets are moving faster than 1.0 m/s

583. Doppler effect depends on

(A) the carrier frequency, the angle between echo source velocity and beam axis, and the reflectivity of blood

(B) the closing velocity between transducer and tissue, carrier frequency, and ultrasound propagation velocity

(D) the largest change in acoustical impedance within the moving blood

584. To calculate blood velocity using color-flow imaging, a sonographer must

(A) place a sample volume in the major streamline or jet within the vessel and set an angle correction parallel to the vessel wall

(B) assume that all flow is parallel to the vessel wall

(D) place a sample volume in the major streamline or jet and set the angle correction parallel to the streamline

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

(A) 0.6 mm

(B) one wavelength or less

(D) 3 dB

586. To preserve flow detail, digital Doppler sampling intervals for a vascular color-flow image must be at intervals of

(A) 1–2 mm

(B) 1–2 cm

(D) –6 dB

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

(A) transmit focusing only

(B) receive focusing only

(D) the speed at which the ultrasound beam is moved by the scanhead

588. The shape of the sample volume in pulsed Doppler has a major effect on the content of the Doppler signal.

(A) true

(B) false

589. To form the color patterns in a Doppler color-flow image, a color-flow system samples down each Doppler image line of sight for

(A) the amplitude of the Doppler signal

(B) the velocities of red blood cells

(D) the velocity spread within the sample site

590. The Doppler portion of a color-flow image is a map of red-cell velocities.

(A) true

(B) false

591. Separating moving soft tissue from moving blood in a color-flow image tests for

(A) Doppler signal amplitudes only

(B) tissue signal amplitudes only

(D) the relationship between the amplitudes and frequencies of the Doppler signals

592. A curving vessel within a color-flow image shows color in the vessel when the beam and vessel are parallel but shows no color, as the vessel turns perpendicular to the beam. The loss of color means that

(A) the vessel is occluded

(B) the vessel is open, but the blood velocity is too low to complete the image

(D) the Doppler effect works only when the vessel is parallel to the ultrasound beam.

593. The smallest vessels that appear in a color-flow image are about 1 mm in diameter. The smaller vessels are absent because

(A) arterial blood velocities are too low in vessels that are less than 1 mm in diameter

(B) the smaller vessels are shadowed by the surrounding soft tissue

(D) the smaller vessels do not reflect ultrasound as well as the larger vessels do

594. The color-flow image provides information on (1) the existence of flow, (2) the location of flow in the image, (3) flow direction relative to transducer, (4) the maximum flow velocity.

(A) all of the above

(B) 1, 3, and 4

(D) 1, 2, and 3

595. Detecting flow in a color-flow imaging system depends on the detection of

(A) changes in Doppler signal amplitude

(B) changes in Doppler signal frequency content

(D) changes in echo signal phase

596. One begins reading a color-flow image by

(A) determining the maximum systolic frequency

(B) knowing the position of the scan plane on the patient’s body

(D) determining the Doppler carrier frequency

597. Changes in the Doppler shift frequencies within a color-flow image sample site appear in the image as

(A) nothing; the image only shows changes in phase

(B) different colors (hues)

(D) different colors (hues) or different levels of saturation (purity)

598. A Doppler color-flow image can show changes in the frequency content at a Doppler sample site by

(A) changes in gray scale

(B) changes in saturation

(D) the introduction of green markers

599. Cardiac color-flow imaging shows changes in the frequency content of the Doppler sample site by

(A) changes in color

(B) changes in saturation

(D) the introduction of red markers

600. Color-flow imaging systems determine the maximum Doppler shift frequency at each sample site.

(A) true

(B) false

601. A measurement of the peak systolic frequency in a carotid artery with a single-point spectrum will be lower than a measurement of the color-encoded frequency at the same point.

(A) true

(B) false

602. The synchronous signal processing uses a Doppler carrier frequency that is the same as the imaging center operating frequency.

(A) true

(B) false

603. Asynchronous signal processing in color-flow imaging requires the same frequency for both Doppler and gray-scale imaging.

(A) true

(B) false

604. Beam steering in asynchronous color-flow imaging is used to provide

(A) a Doppler angle significantly less than 90° to typical blood flow

(B) a way of looking at the same soft tissue targets at an angle different from the perpendicular beams

(D) improved Doppler sensitivity to smaller vessels

605. The mechanical wedge in synchronous color-flow imaging is used to provide

(A) improved penetration through impedance matching

(B) improved beam focusing for the gray-scale image

(D) a Doppler angle between the typical flow patterns in vessels

606. The ability to see flow in deep vessels is limited by the fact that

(A) blood has scattering units that are about the same size as soft tissue

(B) blood is moving faster than the surrounding tissues

(D) blood reflectivity is about 40–60 dB below that of soft tissue

607. Levels of output power and intensity for color-flow imaging are generally higher than those for conventional gray-scale imaging.

(A) true

(B) false

608. Because Doppler signal processing requires more energy, synchronous signal processing always produces Doppler power levels that are higher than those for gray-scale imaging.

(A) true

(B) false

609. In general, tissue ultrasonic intensity levels are higher for single-point spectra than for color-flow imaging with the same system.

(A) true

(B) false

610. Moving from gray-scale only to full-screen color-flow imaging in a system means that the image frame rate will probably do which of the following?

(A) decrease

(B) increase

(D) color signal processing has no effect on frame rate

611. Color-flow imaging in the heart uses larger Doppler sampling intervals to increase the image frame rate than vascular imaging.

(A) true

(B) false

612. Cardiac color-flow imaging also works well in the vascular system because the design can handle the high attenuation rates in cardiac imaging.

(A) true

(B) false

613. Sampling intervals for cardiac color-flow imaging and vascular color-flow imaging are similar.

(A) true

(B) false

614. Cardiac color-flow imaging is limited with a mechanical sector scanner because

(A) the cardiac attenuation rate is too high

(B) the ultrasound beams are always moving

(D) the beam has too many side lobes

615. The phased-array sector scanner and the linear array share common beam forming properties of

(1) a stationary beam at each line of sight,

(2) increased grating lobes with beam steering,

(3) three-dimensional dynamic focusing on receive,

(4) the same aperture sizes for dynamic focusing.

(A) 1 and 2

(B) 1, 2, and 4

(D) all of the above

616. Color-flow imaging in the peripheral vascular system typically uses

(A) the phased sector scan

(B) the linear array scan

(D) a combination of A and B

617. Color-flow imaging in the heart typically uses

(A) the phased sector scan

(B) the linear array scan

(D) a combination of A and C

618. You are imaging a small vessel using 7.5 MHz DCFI with the lowest displayable velocity of 6.0 cm/s. Changing only the carrier frequency to 5.0 MHz will change the lowest displayable velocity to

(A) 1.5 cm/s

(B) 9 cm/s

(D) 15 cm/s

619. Doppler color-flow imaging is unique because it does not have a major problem with high-frequency aliasing.

(A) true

(B) false

620. Both the color and a point spectrum in a stenosis show high-frequency aliasing. One strategy for removing the aliasing involves

(A) doing nothing; aliasing cannot be removed from the system

(B) decreasing the system PRF

(D) decreasing the Doppler angle toward zero

621. Increasing the output power levels and PRF to increase penetration and frame rates opens the system to which of the following artifacts?

(A) high-frequency aliasing

(B) loss of low velocities

(D) range ambiguity

622. The color-coding of red arteries and blue veins and the slow high-resolution frame rates makes the identity of arteries and veins in the abdomen direct and easy.

(A) true

(B) false

623. Turbulence in a vascular color-flow image appears as

(A) a mottled pattern of colors

(B) a mottled pattern of red and blue with changing saturations

(D) A or B

624. Turbulence in a cardiac color-flow image appears as

(A) a mottled pattern of colors

(B) a mottled pattern of red and blue with changing saturations

(D) a mottled green region

625. Power Doppler imaging is so named because

(A) it increases output power for image improvement

(B) it encodes the power spectrum of the Doppler signal into color

(D) none of the above

626. Power Doppler imaging is limited because

(A) it has a serious aliasing problem

(B) it does not work with low carrier frequencies

(D) A and B

627. Power Doppler imaging is a good choice when you

(A) want to show tissue perfusion

(B) want to show tissue velocity

(D) A and B

Page

Contents

If you find an error or have any questions, please email us at admin@doctorlib.info. Thank you!