SPI PRACTICE TEST #2

Three sound waves with identical frequencies of 3 MHz have powers of 2 mW, 5mW and 15 mW. They all travel though three media, wood, brick and fat. The three media have identical thicknesses of 5 cm. Is the following statement true or false? 1. The waves travel through all three media at the same speed since they have identical frequencies. True. False.

Three sound waves with identical frequencies of 3 MHz have powers of 2 mW, 5mW and 15 mW. They all travel though three media, wood, brick and fat. The three media have identical thicknesses of 5 cm. Is the following statement true or false? 2. The sound waves travel through all three media at different speeds because the waves have different powers. True. False.

Three sound waves with identical frequencies of 3 MHz have powers of 2 mW, 5mW and 15 mW. They all travel though three media, wood, brick and fat. The three media have identical thicknesses of 5 cm. Is the following statement true or false? 3. The waves travel through all three media at different speeds because the media are different. True. False.

4. The PRF (pulse repetition frequency) of ultrasound produced by a transducer typical of diagnostic imaging systems: can be changed by the sonographer. depends upon the medium through which the sound travels. remains unchanged as long as the same ultrasound system is used. has nothing to do with ultrasonic imaging.

5. The pulse repetition frequency (PRF) is used to describe certain characteristics of ultrasonic imaging systems. What are its units?. seconds. 1/seconds. mm/us. seconds-2.

6. In diagnostic imaging, what establishes the pulse repetition frequency of a pulsed wave?. the source of the sound. the medium that the pulse travels in. both a and b. neither a nor b.

7. When a sonographer increases the maximum imaging depth during an exam, what happens to the PRF?. increases. frequency decreases. remains unchanged.

8. The pulse repetition frequency is the ______________________. product of the wavelength and propagation speed. reciprocal of the period. sum of the pulse duration and the listening time. reciprocal of the pulse repetition period.

Two ultrasound systems, one producing pulses of 3 MHz frequency and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Is the following statement true or false? 9. The pulses produced by both systems travel at the same speed in the patient. True. False.

Two ultrasound systems, one producing pulses of 3 MHz frequency and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Is the following statement true or false? 10. The PRF of the 6 MHz transducer is greater than the PRF of the 3 MHz transducer. True. False.

Two ultrasound systems, one producing pulses of 3 MHz frequency and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Is the following statement true or false? 11. The period of the 3 MHz sound is greater than the period of the 6 MHz sound. True. False.

Two ultrasound systems, one producing pulses of 3 MHz frequency and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Is the following statement true or false? 12. The wavelength of the 3 MHz ultrasound is greater than the 6 MHz sound. True. False.

13. What does the pulse repetition period depend on?. the source of the sound wave. the medium that the pulse travels in. both a and b. neither a nor b.

14. A sonographer adjusts the output power of the wave emitted by the ultrasound transducer. Which of the following also changes? (More than one answer may be correct). pulse repetition period. PRF. propagation speed. intensity.

15. A sonographer adjusts the maximum imaging depth of an ultrasound system. Which of the following also changes? (More than one answer may be correct). pulse repetition period. wavelength. pulse repetition frequency. frequency.

16. Which of the following is a correct description of pulse repetition period?. the product of wavelength and propagation speed. the reciprocal of the frequency. the sum of the pulse "on" time and the listening "off" time. the time that the transducer is pulsing.

17. What happens to the pulse repetition period if the sonographer decreases the maximum imaging depth achieved in an ultrasound scan?. increases. decreases. remains the same. cannot be determined.

18. What are the units of pulse duration?. units of frequency (Hz, etc.). msec only. units of time (sec, years, etc.). units of distance (feet, etc.).

19. In diagnostic imaging, the pulse duration is determined by______________. the source of the sound wave. the medium that the pulse travels in. both a and b. neither a nor b.

20. What happens to the pulse duration when a sonographer decreases the maximum imaging depth achieved in an ultrasound scan?. increases. decreases. remains the same. cannot be determined.

21. The characteristics of a pulse are as follows: the pulse repetition period is 1000 usec and the listening or dead time is 950 usec. What is the pulse duration?. 1950 usec. 50 msec. 50usec. 0.95.

Is the following statement regarding the pulse duration true or false? 22. The pulse duration of an acoustic wave can be adjusted by a sonographer since it depends upon the pulse's propagation speed. True. False.

Is the following statement regarding the pulse duration true or false? 23. The pulse duration of an acoustic wave can be adjusted by the sonographer since it depends upon the maximum imaging depth. True. False.

Is the following statement regarding the pulse duration true or false? 24. The pulse duration of an acoustic wave cannot be changed by the sonographer unless he or she switches transducers. True. False.

Is the following statement regarding the pulse duration true or false? 25. The pulse duration of an acoustic wave cannot be changed under any circumstances or by any action of the sonographer. True. False.

26. What is the pulse duration of an acoustic wave equal to?. frequency multiplied by period. period multiplied by wavelength. the number of cycles in the pulse divided by the wavelength. period multiplied by the number of cycles in the pulse.

27. Two pulses are produced by different transducers. The pulses are made up of the same number of cycles. The pulse containing cycles of a lower frequency has a: lower pulse repetition frequency. shorter pulse duration. longer pulse duration. longer pulse repetition period.

28. The pulse duration is expressed in the same units as the. period. PRF. wavelenght. density.

29. The spatial pulse length describes certain characteristics of an ultrasound pulse. What are its units?. time. Hertz. meters. none, it is unitless.

30. A typical value for the duty factor (also called the duty cycle) of a pulsed ultrasound wave used in diagnostic imaging is. 0.001 usec. 0.001 kg/cm3. 0.75. 0.001.

31. In the case of pulsed ultrasound, what is the maximum value of the duty factor?. equal to 100. equal to 1. less than 100%. none of the above.

32. What is the value of the duty cycle for continuous wave ultrasound?. 100. 1%. 1000%. none of the above.

33. While using a particular imaging system, what happens to the duty cycle when the maximum imaging depth increases?. increases. decreases. remains the same. cannot be determined.

34. True or False. The instrument operator alters the duty cycle when adjusting the maximum imaging depth of a scan. True. False.

35. True or False. The duty cycle is a characteristic of an ultrasound and transducer system and does not change as long as the system components remain unchanged. True. False.

36. True or False. The pulse duration of an ultrasound and transducer system does not change significantly as long as the system components remain unchanged. True. False.

37. What is the duty factor of a wave that has a pulse repetition period of 30 microseconds and a pulse duration of 0.3 microseconds?. 0.03. 0.90. 30.3. 0.01.

The maximum imaging depth obtained during an exam is unchanged. A new transducer is used that has a longer pulse duration. Is the following statement true or false? 38. The pulse repetition period is increased. True. False.

The maximum imaging depth obtained during an exam is unchanged. A new transducer is used that has a longer pulse duration. Is the following statement true or false? 39. The pulse repetition frequency is increased. True. False.

The maximum imaging depth obtained during an exam is unchanged. A new transducer is used that has a longer pulse duration. Is the following statement true or false? 40.The duty factor is increased. True. False.

The maximum imaging depth obtained during an exam is unchanged. A new transducer is used that has a longer pulse duration. Is the following statement true or false? 41. The frequency is increased. True. False.

42. Which of the following can a sonographer alter while using the same ultrasound machine and transducer? (More than one answer may be correct). pulse repetition period. PRF. frequency. duty cycle. pulse duration.

43. In diagnostic imaging, what determines the spatial pulse length?. the ultrasound system. the medium that the pulse travels in. both a and b. neither a nor b.

44. Which of the following best describes the spatial pulse length?. frequency multiplied by wavelength. PRF multiplied by wavelength. wavelength multiplied by the number of cycles in the pulse. duty factor multiplied by the wavelength.

45. Two transducers send ultrasound pulses into soft tissue. One transducer emits sound with a 4 MHz frequency and the other produces sound at 6 MHz frequency. Each pulse is comprised of 4 cycles. Which has a greater spatial pulse length?. the 6 MHz pulse. the 4 MHz pulse. they are the same. cannot be determined.

46. Using a given transducer and machine, what happens to the spatial pulse length as the sonographer increases the maximum imaging depth?. increases. decreases. remains the same. cannot be determined.

47. True or False. While imaging soft tissue, the spatial pulse length does not change as long as the components of the ultrasound system are the same. True. False.

48. The propagation speed of continuous wave ultrasound is 1.8 kilometers per second. The wave is then pulsed with a duty factor of 0.5. What is the new propagation speed?. 0.5 km/sec. 0.9 km/sec. 1.8 km/sec. 3.6 km/sec. cannot be determined.

49. The frequency of a continuous acoustic wave is 5 MHz. The wave is then pulsed with a duty factor of 0.1. What is the new frequency?. 0.5. 0.5 MHz. 5 MHz. 10 MHz.

50. True or False. The period of an ultrasound wave is related to the frequency of the acoustic signal and is the same regardless of whether the wave is pulsed or continuous. True. False.

51. True or False. The wavelength of an acoustic wave is smaller when it is pulsed rather than continuous. True. False.

52. The term Im defines the ___________________ and has units of __________________. medium's maximum impedance, Rayls. transducer's minimum input, watts. maximum intensity, watts/cm². minimum inductance, Rayls/sec.

53. With a continuous wave sound beam, which of the following 4 intensities are the same?. 1 and 2. 1 and 3. 1 and 4. 2 and 3.

54. The SPTP intensity of a typical pulsed acoustic wave ____________. exceeds the SATA intensity. exceeds the SPTA intensity. exceeds the SATP intensity. all of the above.

With regard to the SPPA intensity, is the following statement true of false? 55. It has a value that is greater than the SPTP intensity. True. False.

With regard to the SPPA intensity, is the following statement true of false? 56. It is only relevant for continuous wave ultrasound. True. False.

With regard to the SPPA intensity, is the following statement true of false? 57. It has a value that is between the SPTP and the SPTA intensities. True. False.

With regard to the SPPA intensity, is the following statement true of false? 58. It can be reported in units of watts per square centimeter. True. False.

59. What does the beam uniformity coefficient measure?. special distribution of sound energy. spatial distribution of acoustic energy. temporal distribution of sound energy. none of the above.

60. Which of the following values can correctly designate both the duty cycle and the beam uniformity coefficient?. 1%. 0. 100%. none of the above.

61. Which one of the following intensities changes when a sonographer adjusts the maximum imaging depth obtained during a sonographic examination?. SPTP. SATA. SATP. SAPA.

62. What are acceptable units for the beam uniformity coefficient?. mW. mW/cm2. cm. none of the above.

63. Two acoustic beams have identical SPTP intensities of 400 mW/cm². One beam is pulsed while the other is continuous wave. Which beam has a higher SPTA intensity?. the pulsed beam. the continuous wave. neither. cannot be determined.

64. The impedance of the matching layer of an ultrasound transducer is 2.6 MRayls and the impedance of the piezoelectric crystal is 3.4 MRayls. If this is assumed to be a good imaging system, what is the best estimate for the impedance of the skin?. 1.5 MRayls. 3.8 MRayls. 3.4 MRayls. 2.8 MRayls.

65. True or False. The piezoelectric crystal of a transducer typically has an impedance higher than the impedance of skin. True. False.

66. The action that will result in a piezoelectric crystal losing its special properties is: breaking it in pieces. exposing it to high temperatures. exposing it to electrical current. exposing it to low pressures.

67. Which temperature is closest to the Curie temperature of the common piezoelectric material known as PZT?. 129° Fahrenheit. 300° Kelvin. 300° centigrade. 300° Fahrenheit.

68. Which of the following properties of the piezoelectric crystal of a continuous wave transducer results in the highest emitted acoustic wave frequency?. thin, high propagation speed. thick, slow propagation speed. thin, slow propagation speed. none of the above.

69. The region from the transducer to the location where the ultrasound beam has its smallest cross-sectional area is called the _________________. focus. half-value thickness. near zone. Fraunhofer zone.

70. The area that starts at the ultrasound beam's smallest diameter and extends deeper is called the: distant zone. Fresnel zone. Fraunhofer zone. depth of penetration.

71. Match the following terms or zones that describe the same regions of an ultrasound beam. 1 and 2, 3 and 4. 1 and 4, 2 and 3. 4 and 6, 5 and 1. 2 and 3, 5 and 1.

72. What is the point or location where an ultrasound beam reaches its smallest dimension?. near zone. focus. penetration depth. focal zone.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 73. The near zone is the only region where the diameter of the sound beam is smaller than the transducer's diameter. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 74. The far zone is the only section where the diameter of the sound beam exceeds the diameter of the transducer. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 75. If the narrowest diameter of the acoustic beam is located at a distance of 8 cm from the transducer face, then the piezoelectric crystal has a diameter of 16 cm. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 76. If the diameter of an acoustic beam is 8 mm at a depth equal to twice the near zone length, then the piezoelectric crystal producing the wave has a diameter of 16 mm. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 77. If the diameter of the acoustic beam produced by the crystal is 8 mm at a depth of twice the near zone length, then the piezoelectric crystal has a diameter of 8 mm. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 78. The near zone is the only region where the diameter of the sound beam decreases. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 79. The higher the frequency of the acoustic wave, the shorter the length of the near zone. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 80. The greater the diameter of a transducer's piezoelectric crystal, the longer is the near zone length. True. False.

A piezoelectric crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Is the following statement true or false? 81. The thicker a transducer's piezoelectric crystal, the longer is the near zone length. True. False.

82. For a disc-shaped piezoelectric crystal producing a continuous acoustic wave, which design will produce a beam with the most shallow focus?. large diameter, low frequency. large diameter, high frequency. small diameter, low frequency. small diameter, high frequency.

83. As a sound wave travels deeply into the far zone, it tends to diverge or spread out. Which of the following will result in a minimum beam divergence deep in the far zone?. small diameter. high frequency. large diameter. low frequency.

84. The Doppler effect is observed as a change in ____________ and has units of _______________. amplitude, watts. power, watts. frequency, per second. wavelength, millimeters.

85. In clinical imaging, which reflectors produce most relevant Doppler shifts?. blood vessels. blood plasma. platelets. red blood cells.

86. If red blood cells are traveling towards a transducer, the frequency emitted by the transducer is __________ the frequency reflected from the blood cells. greater than. equal to. less than.

87. When red blood cells move away from a transducer, the frequency of the wave reflected from the red cells is ___________ the frequency emitted by the transducer. greater than. less than. equal to.

88. What information does the Doppler shift furnish concerning the blood cells that produce it?. frequency. speed. velocity. density.

89. A duplex ultrasound system displays ______________ information. M-mode, 2-dimensional and A-mode. A-mode and B-mode. 2-dimensional and Doppler. 2-dimensional and M-mode.

90. In standard, clinical Doppler ultrasonography, what is known about the reflected frequency produced by red blood cells traveling in a direction away from the transducer?. it is in the audible range. it is ultrasonic. it is greater than the transmitted frequency. it is equal to the transmitted frequency.

91. The Doppler shifts commonly measured in clinical exams are in the range of _________ . -10 kHz to 1 MHz. -0.5 MHz to 0.5 MHz. -0.01 MHz to 0.01 MHz. none of the above.

92. A maximum Doppler shift is obtained when the angle between the direction of blood flow and the direction of the sound beam is __________. 10 degrees. 90 degrees. 180 degrees. 270 degress.

93. The Doppler shift does not always provide a valid estimate of the speed of the red blood cells that produce it because the shift is related to the ________ of the angle between the direction of the beam and the direction of blood flow. sine. tangent. cosine. cotangent.

94. What can be said of the Doppler shift when the sound beam is normally incident to the velocity of the red blood cells?. it is at a maximum. it is half of maximum. it is absent. it is at minimum.

95. Two ultrasound transducers are used to perform Doppler exams on the same patient. The exams are identical except that the transducer frequencies are 5 and 2.5 MHz. Which exam will produce the highest Doppler shift?. the 2.5 MHz exam. the 5 MHz exam. neither. cannot be determined.

96. Two ultrasound transducers are used to perform Doppler exams on the same patient. The exams are identical except that the transducer frequencies are 5 and 2.5 MHz. Which exam will produce the highest velocities?. the 2.5 MHz exam. the 5 MHz exam. neither. cannot be determined.

With regard to continuous wave Doppler, is the following statement true or false? 97. There are a minimum of two distinct piezoelectric crystals in the transducer. True. False.

With regard to continuous wave Doppler, is the following statement true or false? 98. Problems with aliasing significantly limit its clinical utility. True. False.

With regard to continuous wave Doppler, is the following statement true or false? 99. Doppler shifts measured at the transducer could have been produced from many different locations along the ultrasonic beam. True. False.

With regard to continuous wave Doppler, is the following statement true or false? 100. The duty cycle of the wave is 100%. True. False.

101. True or False. The appearance of negative velocities in a pulsed Doppler exam always indicates that red blood cells are moving away from the transducer. True. False.

102. True or False. The appearance of negative velocities on the spectral display of a continuous wave Doppler exam always indicates that red blood cells are moving away from the transducer producing the sound wave. True. False.