Spi Practice Questions 2024/2025

SPI PRACTICE QUESTIONS 2024/2025 _________ is a redirection of US in many directions as a result of a *rough* boundary between two media - RIGHT ANSWER -scattering ___________ resolution is determined by SPL - RIGHT ANSWER -radial or axial ______________ is the distance covered by one cycle - RIGHT ANSWER -wavelength ______________ is the time to complete one cycle - RIGHT ANSWER -period A circular hyperechoic structure is located at a depth of 5 cm. The structure has abnormally low attenuation and the speed in the mass is 1,400 m/s. Which of the following is most likely to appear beneath the structure? - RIGHT ANSWER -reflectors beneath the structure appear abnormally deep in the image A Doppler exam is performed with a 5 MHz probe and a PRF of 15 kHz. Which of these Doppler shifts will create aliasing? - RIGHT ANSWER -14 kHz A hydrophone is used to measure: - RIGHT ANSWER -intensity (or frequency) A pulse is emitted by a transducer and is traveling in soft tissue. The go-return-time, or time-of-flight, of a sound pulse is 130 microseconds. What is the reflector depth? - RIGHT ANSWER -10 cm A quality assurance program: - RIGHT ANSWER -is needed by all labs A shadow appears on an ultrasound scan. Which of the following statements is true about the shadow artifact? - RIGHT ANSWER -it appears as hypoechoic A shadow appears on an ultrasound scan. Which of the following statements is true about the structure immediately above the shadowing artifact? - RIGHT ANSWER -attenuation properties are too high A single element transducer is focused: - RIGHT ANSWER -by the manufacturer A sound beam is created by a single, disc-shaped crystal. Which of these beams has the shallowest focus? - RIGHT ANSWER -2 MHz, 9 mm diameter A sound wave is traveling in the body and propagating from one form of soft tissue to another. For example, sound is moving from muscle to blood. What percentage of the sound wave is most likely to be reflected at the muscle-blood boundary? - RIGHT ANSWER -.5% A sound wave with a frequency of 5 MHz is travelling in soft tissue. What is the wavelength? - RIGHT ANSWER -.3 mm A sound wave's frequency is 10 MHz. The wave is traveling in soft tissue. What is its wavelength? - RIGHT ANSWER -.15 mm A system which is not working well now does not display clear images in the far field. This may be a problem with: - RIGHT ANSWER -transducer, receiver, monitor, or scan converter A transducer converts __________ from one form to another - RIGHT ANSWER -energy A transducer with more than one active element is called: - RIGHT ANSWER -array According to AIUM, there have been no confirmed bioeffects below intensities of ______ watts per square centimeter SPTA - RIGHT ANSWER -.01 Aliasing is an artifact observed when performing Doppler ultrasonography. Which of the following signals is most likely to alias? - RIGHT ANSWER -7 MHz with a PRF of 3 kHz All of the following are limitations of analog scan converts EXCEPT: - RIGHT ANSWER -low spatial resolution All of the following are primarily used to change the overall brightness of an entire image EXCEPT: - RIGHT ANSWER -compensation All of the following are true EXCEPT: - RIGHT ANSWER -two waves with identical frequencies must interfere constructively All of the following are true EXCEPT: - RIGHT ANSWER -two waves with identical frequencies must interfere constructively All of the following are true of normal cavitation EXCEPT: - RIGHT ANSWER -harmful bioeffects are commonly observed All of the following are true regarding temporal resolution EXCEPT: - RIGHT ANSWER -decreased temporal resolution is associated with shorter pulse duration All of the following artifacts place the erroneous reflection below the true reflector EXCEPT: - RIGHT ANSWER -side lobe All of the following describe dynamic range EXCEPT: logarithmic, comparison, relative, absolute, ratio - RIGHT ANSWER -absolute All of the following regarding the hemodynamics of a stenosis are true EXCEPT: - RIGHT ANSWER -pressure is lowest downstream All of the following result from the use of backing material in a transducer EXCEPT: - RIGHT ANSWER -high sensitivity All of the following statements regarding in-vitro bioeffects are true EXCEPT: - RIGHT ANSWER -in-vitro bioeffects conclusions are clinically relevant All of the following will improve temporal resolution EXCEPT: - RIGHT ANSWER -increased line density An image is too dark. Which technique is best to correct this problem? - RIGHT ANSWER -increase receiver gain An individual is standing. The blood pressure generated by the heart is 120 mmHg. What is the hydrostatic pressure at the ankle? - RIGHT ANSWER -100 mmHg An ultrasound system is imaging to a depth of 10 cm. Which of the following will be different on a single image at depths of 2 cm, 5 cm, and 10 cm? - RIGHT ANSWER -lateral resolution An ultrasound system is operating in the harmonic mode. The image on the display of the ultrasound system was created using sound reflections with a frequency of 6 MHz. What is the frequency of sound emitted by the system's transducer? - RIGHT ANSWER -3 MHz An ultrasound system is set at 0 dB and is transmitting at full intensity. What is the output power when the system is transmitting at 10% of full intensity? - RIGHT ANSWER --10 dB An ultrasound system is set at 0 dB and is transmitting at full intensity. What is the output power when the system is transmitting at 50% of full intensity? - RIGHT ANSWER --3 dB An ultrasound system's display is too bright. Which of the following techniques is best to correct this problem? - RIGHT ANSWER -decrease output power An US machine has a digital scan converter, but has an analog input signal. The machine needs to have a: - RIGHT ANSWER -analog to digital converter An US wave travels through two media and has attenuation of 3 dB in the first and 5 dB in the second. What is the total attenuation? - RIGHT ANSWER -8 dB As a result of ______________, the propagation speed increases - RIGHT ANSWER -decreasing compressibility and density As the impedance of two media become vastly different , the: - RIGHT ANSWER -reflection increases Assuming a constant frequency, what happens if the diameter of an unfocused circular transducer is increased? - RIGHT ANSWER -the beam width in the near field is increased At the focus, the beam diameter is __________ the transducer diameter - RIGHT ANSWER -half Attenuation of US in soft tissue is closest to: - RIGHT ANSWER -.6 dB/cm/MHz Biologic effects have not been documented below what intensity? (SPTA) - RIGHT ANSWER -100 mW/cm2 Changing which of the following would not cause any change in a hard copy image output? - RIGHT ANSWER -display brightness and contrast Circumferences may be measured in the unit of: - RIGHT ANSWER -cm Compression is used to: - RIGHT ANSWER -decrease the range of amplitudes Decimal uses a base of 10, binary uses a base of: - RIGHT ANSWER -2 Depth calibration of a machine measures 100 mm spaced wires to be 90 mm apart. Scanning reflectors 50 mm apart, what will the machine calculate the distance to be? - RIGHT ANSWER -45 mm Enhancement artifact appears on an ultrasound scan. Which of the following statements is true about the structure immediately above the artifact? - RIGHT ANSWER -attenuation properties are too low Enhancement, multipath and side lobes result in: - RIGHT ANSWER -artifact For Doppler, which incident angle results in NO shift? - RIGHT ANSWER -90 degrees For soft tissue, the approximate attenuation coefficient in dB/cm is equal to one-half _________ in _________ - RIGHT ANSWER -frequency, MHz From a safety standpoint, which one of the following methods is best? - RIGHT ANSWER -low transmit output and high receiver gain How does frequency compounding improve image quality? - RIGHT ANSWER -reduces speckle How is range ambiguity artifact eliminated? - RIGHT ANSWER -lower the PRF How many bits are needed to represent 1024 shades of gray? - RIGHT ANSWER -10 How many bits are needed to represent 16 shades of grey - RIGHT ANSWER -4 How many cm are 60 mm? - RIGHT ANSWER -6 How many data bits are needed to represent 64 gray shades? - RIGHT ANSWER -6 How much bigger is a billion than a thousand? - RIGHT ANSWER -1,000,000 How much time is required for a sound pulse to travel round trip to and from a reflector that is 2 cm deep in soft tissue? - RIGHT ANSWER -26 microseconds Identify two advantages of coded excitation: - RIGHT ANSWER -improved contrast resolution and penetration If 300,000 cycles occur in a second, what is the wave's frequency? - RIGHT ANSWER -.3 MHz If a 5 MHz sound wave is traveling in the tissues listed below, which will have the longest wavelength? - RIGHT ANSWER -bone If a 5 MHz sound wave is traveling in the tissues listed below, which will have the shortest wavelength? - RIGHT ANSWER -air If a manufacturer changed the lines per frame and kept the imaging depth the same, what else would change? - RIGHT ANSWER -frame rate If a reflector is moved twice as far away from the transducer, how will this affect the time-of-flight of a sound pulse? - RIGHT ANSWER -double it If a wave's amplitude is doubled, what happens to the power? - RIGHT ANSWER -quadrupled If the frame rate increases and the lines per frame is unchanged, what else must happen? - RIGHT ANSWER -depth decreases If the frequency is decreased, the numerical value of the radial resolution is: - RIGHT ANSWER -increased If the frequency of an US wave is doubled, what happens to the period? - RIGHT ANSWER -halved If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength? - RIGHT ANSWER -halved If the frequency of US is increased from 0.77MHz to 1.54MHz, what happens to the propagation speed? - RIGHT ANSWER -remains the same If the intensity is increased by 3 dB, it: - RIGHT ANSWER -doubles If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happened to the power? - RIGHT ANSWER -halved If the lines per frame is increased while the imaging depth is unchanged then: - RIGHT ANSWER -the frame rate decreases If the SPL is 10 mm, what is the axial resolution? - RIGHT ANSWER -.5 cm If the transducer diameter increases, the lateral resolution at its smallest dimension is: - RIGHT ANSWER -increased If we increase frequency, the near zone length is: - RIGHT ANSWER -increased If we increase the transducer diameter, the beam diameter in the far zone is: - RIGHT ANSWER -decreased If wires in an AIUM test object do not appear in the same place as on the display, what is amiss? - RIGHT ANSWER -registration accuracy Images on videotapes are stored using: - RIGHT ANSWER -magnetism Impedance is the _________ of _________ and _________ - RIGHT ANSWER -product, propagation speed, density Impedance is the product of __________ and __________ - RIGHT ANSWER -density and propagation speed Improving the ability to measure the maximum velocity with Doppler is accomplished with all of the following EXCEPT: - RIGHT ANSWER -increasing the transducer's frequency In a B-mode display, which of the following axis are used for the amplitude of the reflection? - RIGHT ANSWER -z-axis In a real-time scanner, which of these choices determines the maximum frame rate? - RIGHT ANSWER -depth of view In an air-tissue interface, what percentage of the US is reflected? - RIGHT ANSWER -near 100% In B-mode, which input is used with the amplitude of reflection? - RIGHT ANSWER -z-axis In soft tissue: Distance traveled = __________ x round trip time - RIGHT ANSWER -propagation speed In which of these biologic tissues will sound waves propagate most quickly? - RIGHT ANSWER -tendon In which of these media will sound travel the slowest? - RIGHT ANSWER -high density, low stiffness In which way is an annular phase array transducer different than a linear phased array transducer? - RIGHT ANSWER -the annular is steered mechanically Lateral resolution can be improved by: - RIGHT ANSWER -focusing List the following in increasing order: deci, kilo, micro, mega, milli - RIGHT ANSWER -micro, milli, deci, kilo, mega Multiple reflections that are equally spaced are called: - RIGHT ANSWER -reverberations Post processing occurs when the image: - RIGHT ANSWER -entered the A/D converter but before display Power of sound has units of: - RIGHT ANSWER -watts Pre-processing occurs: - RIGHT ANSWER -when the patient is scanned Propagation speed = ______________ x wavelength - RIGHT ANSWER -frequency Put in decreasing order of propagation speed: gas, liquid, solid - RIGHT ANSWER -solid, liquid, gas Put in decreasing order: deci, deca, micro, centi - RIGHT ANSWER -deca, deci, centi micro Put in increasing order of propagation speed: bone, water, air - RIGHT ANSWER -air, water, bone Quality assurance studies should be performed: - RIGHT ANSWER -routinely Rayl is the unit of: - RIGHT ANSWER -impedance Rectification and smoothing are components of: - RIGHT ANSWER -demondulation Refraction only occurs if there are: - RIGHT ANSWER -oblique incidence and different propagation speeds Reject is used to: - RIGHT ANSWER -adjust the appearance of lowly reflective objects Snell's law describes the physics of: - RIGHT ANSWER -refraction Sound intensity is decreased by 75%. How many decibels of attenuation is that? - RIGHT ANSWER -6 dB Sound is traveling from medium 1 to medium 2. Propagation speeds of M1 is 1,600 m/s and M2 is 1,500 m/s. There is oblique incidence - RIGHT ANSWER -angle of incidence = angle of reflection Sound waves are: - RIGHT ANSWER -longitudinal, mechanical T/F: A sonographer's education ends when they become registered - RIGHT ANSWER -false T/F: A sound wave is made of compressions and rarefactions - RIGHT ANSWER -true T/F: Axial resolution is affected by focusing - RIGHT ANSWER -false T/F: Doppler shifts ALWAYS occur is the sound source and receiver are in motion - RIGHT ANSWER -false T/F: Doppler shifts are always created when the source and receiver are in motion relative to each other - RIGHT ANSWER -false T/F: Gray scale can be changed by the sonographer - RIGHT ANSWER -true T/F: Increasing the frequency increases the penetration depth - RIGHT ANSWER -false T/F: Lateral resolution is also called azimuthal - RIGHT ANSWER -true T/F: Lateral resolution is also called longitudinal - RIGHT ANSWER -false T/F: Shadowing artifact is unrelated to the speed of sound in a medium - RIGHT ANSWER -true T/F: Shadowing may result from high amounts of reflection of US energy - RIGHT ANSWER -true T/F: Sonographers cannot affect a patient's exposure to acoustic energy - RIGHT ANSWER -false T/F: The sonographer CANNOT change, directly or indirectly, the duty factor of an US machine - RIGHT ANSWER -false T/F: There have NOT been biological effects from US found in the labratory - RIGHT ANSWER -false T/F: With normal incidence, the angle is 180 degrees. - RIGHT ANSWER -false T/F: With right angle incidence, reflections are always generated at a boundary if the propagation speeds of the media are different - RIGHT ANSWER -false The angle between two media is 56 degrees. This is called: - RIGHT ANSWER -oblique incidence The angle between two media is 90 degrees. What is this called? - RIGHT ANSWER -orthogonal incidence The angle of incidence of an US beam is perpendicular to an interface. The two media have the SAME propagation speeds. What process cannot occur? - RIGHT ANSWER -refraction The consolidation of many images into a single frame best describes which of the following? - RIGHT ANSWER -persistence The creation of an image by scanning from different angles best describes: - RIGHT ANSWER -spatial compounding The Curie temperature has which effect? - RIGHT ANSWER -the ferroelectric material is depolarized The dB is defined as the __________ of two intensities - RIGHT ANSWER -ratio The distance to a target is doubled. The time-of-flight for a pulse to travel to the target and back is: - RIGHT ANSWER -doubled The Doppler shift is a measure of: - RIGHT ANSWER -difference between incident & reflected frequencies The Doppler shift is the __________ of two frequencies - RIGHT ANSWER -difference The duty factor for CW ultrasound is: - RIGHT ANSWER -1.0 The dynamic range is the ratio of the smallest to the largest ____________ that a system can process without distortion - RIGHT ANSWER -amplitude The effects of soft tissue on ultrasound are called: - RIGHT ANSWER -acoustic propagation properties The fill-in of anechoic structures such as cysts is known as all of the following EXCEPT: - RIGHT ANSWER -ghosting artifact The frequency closest to the lower limit of ultrasound is: - RIGHT ANSWER -15,000 Hz The Fresnel zone is the: - RIGHT ANSWER -near zone The fundamental frequency of a transducer is 2.5 MHz. What is the second harmonic frequency? - RIGHT ANSWER -5 MHz The general mechanism which creates harmonics is called: - RIGHT ANSWER -non-linear behavior The more bits per pixel: - RIGHT ANSWER -the more shades of gray The more pixels per inch: - RIGHT ANSWER -better spatial resolution The most likely amount of reflection at a boundary between soft tissues is: - RIGHT ANSWER -1% The most typical amount of transmission at a boundary in biologic media is: - RIGHT ANSWER -99% The process of reducing the difference between the smallest and largest voltages is called: - RIGHT ANSWER -compression The production of a voltage from deformation is called: - RIGHT ANSWER -piezoelectricity The propagation speed of US in the AIUM test object is: - RIGHT ANSWER -1.54 mm/microseconds The range equation relates distance from the reflector to: - RIGHT ANSWER -time-of-flight and propagation speed The region from the transducer to the minimum beam cross-sectional area is the: - RIGHT ANSWER -fresnel zone The relative output of an US instrument is calibrated in dB and the operator increases the output by 60 dB. The beam intensity is increased by which of the following? - RIGHT ANSWER -1,000,000 The speed of sound in soft tissue is closest to: - RIGHT ANSWER -1,500 m/s The time from the beginning of a pulse until its end is ______________? - RIGHT ANSWER -pulsed duration The units of attenuation are ______; this is a ______________ scale - RIGHT ANSWER -dB, logarithmic The units of PRF are: - RIGHT ANSWER -per minute To measure the US beam intensity, use a: - RIGHT ANSWER -calibrated hydrophone Traveling through the same medium, if the frequency is doubled, the propagation speed is: - RIGHT ANSWER -unchanged Traveling through the same medium, if the frequency is doubled, the wavelength is: - RIGHT ANSWER -halved Two objects start at the same point. One object moves towards the west at 5 miles per hour. The other object moves towards the west at 15 miles per hour. A sound wave is sent from the first object to the second to measure a Doppler frequency. Which of the following statements is true? - RIGHT ANSWER -the doppler frequency will be negative Under which circumstance is cavitation most likely to occur? - RIGHT ANSWER -low frequency and high signal amplitude Under which condition is axial resolution improved? - RIGHT ANSWER -decreased pulse duration Under which of the following conditions is axial resolution improved? - RIGHT ANSWER -decreased SPL Under which of the following conditions is lateral resolution improved? - RIGHT ANSWER -decreased beam diameter Volume has which of the following units? - RIGHT ANSWER -cm^3 What are attenuation's three components? - RIGHT ANSWER -scattering, reflection, absorption What are the units of intensity? - RIGHT ANSWER -watts/cm2 What are the units of longitudinal resolution? - RIGHT ANSWER -feet What are typical clinical Doppler frequencies? - RIGHT ANSWER -1-10,000 Hz What artifact has a grainy appearance and is caused by the interference effects of scattered sound? - RIGHT ANSWER -speckle What best describes the features of a sound wave and medium that determine the speed of sound? - RIGHT ANSWER -density and stiffness What can pulsed Doppler measure that continuous wave cannot? - RIGHT ANSWER -location What component of a transducer changes electrical to mechanical and mechanical back to electrical energy? - RIGHT ANSWER -PZT What component of the US unit contains the memory bank? - RIGHT ANSWER -scan converter What determines the center frequency of a transducer? - RIGHT ANSWER -thickness What determines the frequency of a sound beam from a pulsed transducer? - RIGHT ANSWER -PZT thickness What determines the spatial resolution of a monitor? - RIGHT ANSWER -the number of lines per frame What determines whether reflection will occur when a sound beam strikes a boundary at normal incidence? - RIGHT ANSWER -impedance differences What does a hydrophone measure? - RIGHT ANSWER -acoustic output of an ultrasound imaging system What Doppler angle is most inaccurate? - RIGHT ANSWER -60-75 degrees What happens to the speed of sound in a medium when the bulk modulus of the medium decreases? - RIGHT ANSWER -slower What happens to the speed of sound in a medium when the bulk modulus of the medium increases? - RIGHT ANSWER -faster What happens to venous blood flow to the heart during expiration? - RIGHT ANSWER -decreased What has the greatest influence upon color jet size? - RIGHT ANSWER -color doppler gain settings What increases patient exposure? - RIGHT ANSWER -exam time What information does Doppler shift provide? - RIGHT ANSWER -velocity What is another name for longitudinal resolution? - RIGHT ANSWER -axial or depth What is displayed on the x-axis of an M-mode image? - RIGHT ANSWER -time What is displayed on the y-axis of an M-mode image? - RIGHT ANSWER -time-of-flight What is NOT associated with PACS? - RIGHT ANSWER -analog replay What is NOT related to CW wave transducers? - RIGHT ANSWER -wide bandwidth What is not the responsibility of the sonographer? - RIGHT ANSWER -adjust converter matrix What is NOT true regarding normal cavitation? - RIGHT ANSWER -harmful bioeffects are commonly observed What is related to frequency to the 4th power? - RIGHT ANSWER -rayleigh scattering What is the *fraction* of time that a transducer is transmitting? - RIGHT ANSWER -duty factor What is the accuracy of reflector depth called? - RIGHT ANSWER -depth calibration What is the accuracy of reflector depth position on an A, B, or M-mode display called? - RIGHT ANSWER -depth calibration What is the actual time that an US machine is creating a pulse? - RIGHT ANSWER -pulse duration What is the approximate attenuation coefficient of 1 MHz US in soft tissue? - RIGHT ANSWER -.5 dB/cm What is the elimination of voltages that do NOT exceed a certain level? - RIGHT ANSWER -reject What is the first thing you should do when entering a hospital room? - RIGHT ANSWER -check the patient's wristband for identification What is the Fraunhofer zone? - RIGHT ANSWER -far zone What is the frequency of a wave with a 1 msec period? - RIGHT ANSWER -1 KHz What is the greatest advantage of one and one-half dimensional array transducers? - RIGHT ANSWER -improved slice thickness resolution What is the location of the minimum cross-sectional area of the US beam called? - RIGHT ANSWER -focus What is the meaning of a thermal index = 3? - RIGHT ANSWER -tissue temperature may rise 3 degrees celsius What is the minimum value of the duty factor? - RIGHT ANSWER -0% What is the most common cause of localized vertical non-uniformity in a real-time B-mode image? - RIGHT ANSWER -defective transducer elements What is the most typical Doppler shift measured clinically? - RIGHT ANSWER -2 kHz What is the name of the receiver function that corrects for attenuation? - RIGHT ANSWER -compensation What is the Nyquist limit if a pulsed-wave doppler instrument has a pulse repetition frequency of 16 kHz? - RIGHT ANSWER -8 kHz What is the propagation speed determined by? - RIGHT ANSWER -density and elasticity What is the range of frequencies created by medical diagnostic Doppler transducers? - RIGHT ANSWER -2-10 MHz What is the significance of gray scale variation in the spectrum of a pulse wave Doppler display? - RIGHT ANSWER -it represents the number of RBC's creating the reflection What is the standard for communication between medical imaging computers? - RIGHT ANSWER -DICOM What is the wavelength of a 3 MHz sound pulse in soft tissue? - RIGHT ANSWER -.49 mm What may be a unit of amplitude? - RIGHT ANSWER -cm What measures the output of a transducer? - RIGHT ANSWER -hydrophone What will increase signal-to-noise ratio? - RIGHT ANSWER -increasing output power What will NOT improve temporal resolution? - RIGHT ANSWER -increased line density When a fluid is flowing at a slow and constant rate within a long tube having a uniform diameter, which is the nature of the flow? - RIGHT ANSWER -laminar When may a patient revoke their consent to be treated? - RIGHT ANSWER -at any time When the focal point in a B-mode image is electronically changed, which type of focusing is in use? - RIGHT ANSWER -dynamic When the US machine displays only strong reflecting objects and nothing else, the sonographer should: - RIGHT ANSWER -increase output power Where are harmonics created? - RIGHT ANSWER -in the tissues Where does coded excitation originate? - RIGHT ANSWER -the pulser Which action can improve resolution of a displayed image? - RIGHT ANSWER -increasing the transducer frequency Which angle of insonation to blood flow produces the maximum doppler shift: 180, 150, 90, 45 degrees - RIGHT ANSWER -180 (same as zero) Which best describes annular array transducers? - RIGHT ANSWER -excellent lateral resolution, diminished temporal resolution, sector shaped Which component of an ultrasound system exposes the patient to the greatest risk? - RIGHT ANSWER -transducer Which control allows adjustment for attenuation at specific depths? - RIGHT ANSWER -TGC Which factor determines the displayed depth of a reflector? - RIGHT ANSWER -PRF Which factor reduces the likelihood of aliasing in pulsed wave spectral doppler? - RIGHT ANSWER -increased nyquist limit Which has the *greatest* amount of attenuation? - RIGHT ANSWER -bone Which imaging mode requires two elements mounted side by side? - RIGHT ANSWER -CW doppler Which is most likely to create cavitation? - RIGHT ANSWER -high peak rarefaction pressure and low frequency Which is not a part of the transducer? - RIGHT ANSWER -A/D converter Which is not an acoustic variable? - RIGHT ANSWER -intensity Which of the following best describes a linear sequential array transducer? - RIGHT ANSWER -dynamic receive focusing, rectangular shaped Which of the following best describes a sound beam? - RIGHT ANSWER -a collection of mechanical vibrations in the form of compressions and rarefactions Which of the following best describes a vector array transducer? - RIGHT ANSWER -electronic steering and focusing, trapezoidal shape Which of the following best describes demodulation of electronic signals? - RIGHT ANSWER -changing the shape or form of the signal Which of the following best describes the *empirical* approach to the study of bioeffects? - RIGHT ANSWER -exposure-response Which of the following best describes the *mechanistic* approach to the study of bioeffects? - RIGHT ANSWER -cause-effect Which of the following best describes the features of a sound wave and medium that determine the speed of sound in the medium? - RIGHT ANSWER -density and stiffness of the medium Which of the following choices best describes an ideal epidemiological bioeffects study? - RIGHT ANSWER -randomized and prospective Which of the following choices best describes axial resolution artifact? - RIGHT ANSWER -two reflectors positioned in front of the other appears as one reflection Which of the following choices determines the signal amplitude in the transducer of an ultrasound system? - RIGHT ANSWER -reflected intensity of the sound beam Which of the following choices determines the signal amplitude in the transducer of an ultrasound? - RIGHT ANSWER -reflected intensity Which of the following clinical modalities has the lowest output intensity? - RIGHT ANSWER -gray scale imaging Which of the following describes the situation where the minimum amount of attenuation will occur? - RIGHT ANSWER -4 cm depth and 6 MHz frequency Which of the following forms of cavitation are most likely to produce micro-streaming in the intracellular fluid and shear stresses? - RIGHT ANSWER -stable cavitation Which of the following forms of focusing is achieved during reception? - RIGHT ANSWER -dynamic aperture Which of the following functions of a receiver is used to create similar brightness reflections from identical reflectors positioned at different depths in the body? - RIGHT ANSWER -compensation Which of the following has a propagation speed closes to soft tissue? - RIGHT ANSWER -muscle Which of the following has the greatest influence on temporal resolution? - RIGHT ANSWER -propagation speed and image depth Which of the following has the greatest output intensity? - RIGHT ANSWER -pulsed doppler Which of the following improves signal-to-noise ratio? - RIGHT ANSWER -frame averaging Which of the following is a benefit of using a contrast agent? - RIGHT ANSWER -increased amplitude of the returning doppler signals Which of the following is associated with cavitation? - RIGHT ANSWER -mechanical index Which of the following is associated with power Doppler? - RIGHT ANSWER -poor temporal resolution and flash artifact Which of the following is determined by the source and the medium? - RIGHT ANSWER -range resolution Which of the following is most directly related to temporal resolution? - RIGHT ANSWER -frame rate Which of the following is not a beam steering technique for a mechanical scanhead? - RIGHT ANSWER -phased beam Which of the following is NOT used to measure the output of ultrasound systems? - RIGHT ANSWER -calibrated absorpterometer Which of the following is proportional to the square of the amplitude? - RIGHT ANSWER -power Which of the following is the best lateral resolution? - RIGHT ANSWER -.06 cm Which of the following is the cause of slice thickness artifact? - RIGHT ANSWER -beam dimension greater in size than the reflector Which of the following is the correct order of receiver operation? - RIGHT ANSWER -amplification, demodulation, reject Which of the following is the spectral analysis technique of choice for PW and CW Doppler? - RIGHT ANSWER -FFT Which of the following lists is in decreasing order? kilo, deci, micro, hecto, milli, nano - RIGHT ANSWER -kilo, hecto, deci, milli, micro, nano Which of the following situations should result in a cessation of the use of diagnostic ultrasound? - RIGHT ANSWER -the benefits are out-weighted by the risks Which of the following sound waves is ultrasonic and least useful? - RIGHT ANSWER -30 KHz Which of the following statements about Doppler is most correct? - RIGHT ANSWER -non-directional Doppler uses non-coherent processing, while bi-directional Doppler uses phase-quadrature processing Which of the following statements related to venous flow is most correct? - RIGHT ANSWER -during inspiration, venous flow in the arms increases & during expiration, venous flow in the legs increases Which of the following steps is performed just prior to storage of image data in a digital scan converter? - RIGHT ANSWER -A-to-D conversion Which of the following tissues will most likely create Rayleigh scattering? - RIGHT ANSWER -red blood cells Which of the following transducers will create a sound beam with the least amount of divergence? - RIGHT ANSWER -high frequency, large diameter Which of the following transducers will create sound with the lowest frequency? - RIGHT ANSWER -thick crystal, PZT in which sound travels slowly Which of the following will have the lowest SPTA intensity at a depth of one near zone? - RIGHT ANSWER -4 MHz, 12 mm diameter Which of the following will reduce ghosting artifact? - RIGHT ANSWER -wall filter Which of the following will result in the greatest number of shades of gray in a digital image display? - RIGHT ANSWER -large pixels with many bits/pixel Which of the following will result in the highest mechanical index? - RIGHT ANSWER -low frequency and high signal amplitude Which of these biologic tissues will sound waves propagate most quickly? - RIGHT ANSWER -tendon Which of these boundaries will create the strongest reflection? - RIGHT ANSWER -air-soft tissue Which of these boundaries will create the weakest reflection? - RIGHT ANSWER -soft tissue-blood Which of these cannot be performed by the sonographer? - RIGHT ANSWER -clean pixels Which of these factors has the greatest influence on PRP? - RIGHT ANSWER -display depth Which of these intensities is the smallest? SATP, SPTP, SATA - RIGHT ANSWER -SATA Which of these statements is true of a 25 MHz sound pulse? - RIGHT ANSWER -highly attenuating, short SPL Which of these terms does NOT belong with the others? high duty factor, shallow imaging, short pulse duration, short PRP, high PRF - RIGHT ANSWER -short pulse duration Which of these terms does NOT belong with the others? gray scale, few choices, uncompressed signal, wide dynamic range, low contrast - RIGHT ANSWER -few choices Which of these terms means "many gray shades"? - RIGHT ANSWER -wide dynamic range Which one of the following sets of properties of a test phantom is most relevant when assessing depth calibration accuracy? - RIGHT ANSWER -reflector spacing and propagation speed Which receiver function cannot be adjusted by the sonographer? - RIGHT ANSWER -demodulation Which setting of an ultrasound system gives the sonographer the ability to display both strong and weak echoes? - RIGHT ANSWER -dynamic range Which technique increases the sharpness of high contrast boundaries? - RIGHT ANSWER -edge enhancement Which technique results in a 3D image? - RIGHT ANSWER -surface rendering Which technique utilizes modulation of the transmitted pulse to improve signal-to-noise ratio? - RIGHT ANSWER -coded excitation Which transducer would be best to image superficial structures? - RIGHT ANSWER -small diameter, high frequency Which type of artifact appears most commonly with highly reflective objects? - RIGHT ANSWER -shadowing Which type of interaction between sound and tissue is most affected by the thermal index? - RIGHT ANSWER -absorption Which type of transducer will have the shallowest focus? - RIGHT ANSWER -low frequency, small diameter Which variable decreased when the number of acoustic lines per frame is increased without changing the maximum depth? - RIGHT ANSWER -frame rate While propagating, a sound wave is refracted. Finally, it returns to the transducer. The system processes the sound wave as if it has: - RIGHT ANSWER -traveled in a straight line, reflected, and returned While scanning in a water tank, what location in a sound beam has the highest intensity? - RIGHT ANSWER -focal zone With an unfocused transducer, what is the area from the face of the transducer to where the beam diverges called? - RIGHT ANSWER -near field With good images on the display but not on the printer, one should: - RIGHT ANSWER -adjust the recorder With normal incidence, what factors affect refraction? - RIGHT ANSWER -none of the above With phased array transducers, tiny time delays are used to steer the sound beams in different directions. Which component of an ultrasound system creates these time delays? - RIGHT ANSWER -beam former With the presence of __________, we see more boundaries than there are reflecting surfaces - RIGHT ANSWER -reverberations You are performing a quality assurance study on an ultrasound system using a tissue equivalent phantom. You make an adjustment using a knob on the system console that changes the appearance of reflector brightness from fully bright to barely visible. What are you evaluating? - RIGHT ANSWER -system sensitivity You enter a room only to find the patient does not speak English. Which of the following is best to obtain informed consent? - RIGHT ANSWER -call for a hospital interpreter