Davies Ultrasound Physics Review

What action below would be most in keeping with the ALARA principle while performing a diagnostic ultrasound examination?

A: Allow multiple students to scan an obstetrical patient because the fetus is in a good position for imaging.

B: Prolong the sonogram to make videos of the fetus for each family member.

C: Complete the diagnostic scan in a timely fashion at the lowest output power that achieves a quality image.

D: Maximize the acoustic output to brighten the overall image.

E: Extend the sonogram beyond the intended scope of the exam requisition.

C: Complete the diagnostic scan in a timely fashion at the lowest output power that achieves a quality image.

During performance of an obstetrical ultrasound exam you adjust the system parameters to improve the image. Which of the following parameters would increase acoustic exposure?

A: Increase gain

B: Increase TGC

C: Increase frequency

D: Increase transmit power

E: Increase frame averaging

D: Increase transmit power

While performing a sonogram to minimize risk to the fetus which imaging mode trade off would be most applicable?

A: Use M-mode instead of pulsed-wave Doppler to measure the fetal heart rate.

B: Use color Doppler instead of power Doppler to image the umbilical cord.

C: Use pulsed-wave Doppler instead of power Doppler to evaluate the fetal heart.

D: Use harmonics instead of fundamental to image the fetal spine.

E: All of the above.

A: Use M-mode instead of pulsed-wave Doppler to measure the fetal heart rate.

What potential bioeffect occurs through absorption of sound energy by tissue?

A: Cavitation

B: Heating

C: Attenuation

D: Reflection

E: Refraction

B: Heating

When practicing universal precautions you should do all of the following EXCEPT:

A: Wear gloves when there is a potential for contact with patient bodily fluids.

B: Change gloves when moving from one patient to another.

C: Wash hands immediately after gloves are removed.

D: Wear face masks or eye protection whenever there is a possibility of blood splashing into your face.

E: Wash gloves between exams for re-use from one patient to another.

E: Wash gloves between exams for RE-use from one patient to another.

A nosocomial infection is defined as one that is:

A: Resistant to antibiotics

B: Restricted to the respiratory system

C: Hospital-acquired

D: Not contagious

E: Requires isolation

C: Hospital-acquired

Thermally induced biological effects should be preventable by avoiding a local tissue temperature increase exceeding:

A: 1 degree C

B: 4 degrees C

C: 10 degrees C

D: 95 degrees F

E: None; thermal effects have no threshold.

A: 1 degree C

Which intensity descriptor has the lowest numerical value for the characterization of a pulsed-wave ultrasonic field?

A: SATA

B: SPTA

C: SATP

D: SPTP

E: These intensity descriptors are only used for continuous-wave ultrasound.

A: SATA

Increased tissue heating could occur when you:

A: Decrease frequency.

B: Increase transmit power.

C: Decrease exposure time.

D: Decrease pulse repetition frequency.

E: All of the above

B: Increase transmit power.

A study designed to determine if there is an association between an adverse effect in a population and exposure to a particular agent is a(n):

A: Case report

B: Epidemiological study

C: In vitro study

D: In vivo study

E: Single-incident investigation

B: Epidemiological study

Which of the following actions is NOT compliant with HIPAA?

A: Cropping all patient identifiers from images used for teaching purposes.

B: Refraining from disclosing patient health information without proper authorization.

C: Reviewing your neighbors medical studies on your hospital PACS system so you can give her your opinion of her condition.

D: Covering your daily requisition list so that the names are not visible to patients and visitors.

E: All of these actions are compliant with HIPAA.

C: Reviewing your neighbors medical studies on your hospital PACS system so you can give her your opinion of her condition.

What does mechanical index indicate on an ultrasound system?

A: The maximum temperature increase in tissue

B: The minimum temperature increase in tissue

C: Acoustic power in milliwatts

D: The likelihood of cavitation during an ultrasound exam

E: Minutes of exposure time before tissue heating is too great

D: The likelihood of cavitation during an ultrasound exam

In medicine what do the initials "PHI" indicate?

A: Private health indicator

B: Personal heart index

C: Personal health information

D: Private health institute

E: Protected health information

E: Protected health information

What should you limit when the thermal index exceeds 1?

A: Overall gain

B: TGC

C: Exposure time

D: Scanning depth

E: All of the above

C: Exposure time

To practice the ALARA principle which of the following techniques should you employ?

A: Always use the least amount of Reciever gain that allows adequate tissue visualization.

B: Adjust the controls so that the MI and TI read outs exceed 1.

C: Use the lowest transmit power that allows adequate tissue visualization.

D: Use the highest frame averaging setting.

E: Maximize exposure time.

C: Use the lowest transmit power that allows adequate tissue visualization.

The thermal index indicates:

A: Estimated maximum temperature increase in tissue

B: Minutes of exposure time before heating is too great

C: Seconds of exposure time before heating is too great

D: Acoustic power in milliwatts

E: Liklihood of cavitation

A: Estimated maximum temperature increase in tissue.

Which operator control most directly adjusts the intensity of the transmitted pulse?

A: Receiver gain

B: Depth of scanning

C: Acoustic output (transmit) power

D: Time gain compensation (TGC)

E: Pulse repetition frequency

C: Acoustic output (transmit) power

Which of the following would show the highest intensity value?

A: SATP

B: SATA

C: Im

D: SPPA

E: SPTP

E: SPTP

Which intensity parameter is not applicable for continuous-wave ultrasound?

A: SATA

B: SPTA

C: SPPA

D: SAPA

E: C and D

E: C and D

Which of the following would most likely have the highest SPTA value?

A: CW Doppler

B: B-mode real-time scanners

C: Static B-mode scanners

D: PW Doppler

E: Fetal monitor Doppler

D: PW Doppler

Using a hydrophone you can measure?

A: Impedance

B: Pressure amplitude

C: Duty factor

D: All of the above

E: B and C only

E: B and C only

Which of the following parameters relates to tissue heating?

A: Absorption

B: Impedance

C: Refraction

D: Propagation speed

E: All of the above

A: Absorption

Which of the following occurs when you use the maximum system gain?

A: Increased tissue heating

B: Increased risk of cavitation

C: Fluid particle streaming

D: Increased sound absorption

E: None of the above

E: None of the above

You are performing a sonogram and notice that the thermal index (TI) is greater than 1. Any increase in temperature would be greatest in:

A: Liver

B: Lung

C: Kidney

D: Bone

E: Bladder

D: Bone

The motion of particles in a fluid is sometimes observed in an intense ultrasound beam. This is termed:

A: Acoustic streaming

B: Transient cavitation

C: Thermal interaction

D: Rarefaction

E: Compression

A: Acoustic streaming

You are performing a sonogram and notice that the TI reading is 1. What does this indicate?

A: The patients temperature has increased 1 degree C as a result of the ultrasound scan.

B: The patients temperature has increased 2 degrees C as a result of the ultrasound scan.

C: You must limit your scanning to 1 minute.

D: The output level is high enough that temperature could increase as much as 1 degree C if the transducer were held stationary.

E: The temperature at the focal point has increased by 1 degree C and scanning time must be reduced to 4 minutes

D: the output level is high enough that temperature could increase as much as 1 degree C if the transducer were held stationary.

What sonographic application has the lowest FDA-approved SPTA values?

A: Cardiac

B: Opthalmic

C: Peripheral vascular

D: Fetal imaging

E: Abdominal

B: Opthalmic

The following advantage is associated with use of the MI and TI indices:

A: The system will automatically adjust parameters to limit exposure under adverse conditions.

B: The system will beep to notify the sonographer when indices are too great.

C: The system will shut down when exposure becomes too great.

D: The sonographer can easily dial in a safe exposure limit for each patient.

E: Information is available on the screen to help the sonographer implement the ALARA principle.

E: Information is available on the screen to help the sonographer implement the ALARA principle.

When scanning with pulsed-wave Doppler you would affect the acoustic exposure by changing which of the following?

A: Doppler gain

B: High pass filter

C: Pulse repetition frequency

D: Baseline position

E: Doppler angle

C: Pulse repetition frequency

What should you do to avoid nosocomial and cross-infection with sonographic probes?

A: Probe cleaning should always precede high-level disinfection.

B: Covering a probe with a condom is a sufficient barrier to infection for intracavitary probes.

C: Disinfection using a germicide compatible with the transducer is indicated when the probe is in contact with mucous membranes.

D: Alcohol soak of each probe should occur between patients.

E: A and C

E: A and C

The mass you are imaging has a diameter of 35mm. This value can also be expressed as:

A: 350 cm

B: 0.35 cm

C: 3.5 cm

D: 35 m

E: 3.5 m

C: 3.5 cm

Relative measurement of intensity based on a logarithmic scale is expressed in:

A: Newtons per cm squared

B: Watts per cm squared

C: Decibels

D: Pascals

E: Neper

C: Decibels

Which prefix equals 10-3?

A: Micro

B: Milli

C: Mega

D: Centi

E: None of the above

B: Milli

When you change the transmit frequency which of the following is altered?

A: Displacement amplitude of the particles in the medium.

B: Speed at which the sound wave propagates through the medium.

C: Number of cycles per second.

D: Pulses transmitted per second.

E: Number of electrical impulses applied to the transducer per second.

C: Number of cycles per second.

While performing a Doppler ultrasound examination you adjust the pulse repetition frequency to 12 kHz. This can also be expressed as:

A: 0.12 Hz

B: 1200 Hz

C: 1.2 MHz

D: 12,000 Hz

E: 120 MHz

D: 12,000 Hz

In sound wave propagation a region of elevated pressure is termed:

A: Compression

B: Demodulation

C: Rarefaction

D: Period

E: Resonance

A: Compression

When you switch from a 2.5 MHz to a 5 MHz transducer the sound wavelength:

A: Doubles

B: Quadruples

C: Halves

D: Quarters

E: Is unaffected

C: Halves

Wavelength depends on what two factors?

A: Frequency and amplitude.

B: Amplitude and propagation speed.

C: Period and frequency.

D: Frequency and propagation speed.

E: Amplitude and intensity.

D: Frequency and propagation speed.

Which of the following human tissues has the highest rate of attenuation of an ultrasound wave?

A: Liver

B: Fat

C: Fluid

D: Lung

E: Blood vessels

D: Lung

The propagation speed for sound is lowest in which of the following biological tissues?

A: Fat

B: Blood

C: Muscle

D: Bone

E: Liver

A: Fat

Which of the following factors does NOT affect impedance?

A: Stiffness

B: Density

C: Propagation speed

D: Frequency

E: All of the above affect impedance.

D: Frequency

You are imaging a structure containing two media having the same acoustic impedance. What will occur at the boundary of the two structures?

A: All of the sound will be transmitted.

B: All of the sound will be reflected.

C: Some of the sound will be refracted.

D: Some of the sound will be reflected and some of the sound will be transmitted.

E: Most of the sound will be absorbed at the media boundary.

A: All of the sound will be transmitted.

What is the purpose of the gel coupling between the transducer and the skin?

A: To reduce heating of the epidermis caused by sound absorption and friction.

B: To soften the skin and soothe the patient.

C: To provide a medium for sound transmission since ultrasound does not propagate through air.

D: To reduce the impedance differences between the transducer and the skin.

E: To lessen refraction of the sound at the skin surface and improve sound transmission.

C: To provide a medium for sound transmission since ultrasound does not propagate through air.

The unit of impedance is the:

A: Joule

B: Rayl

C: Watt/cm2

D: Newton

E: Watts/cm

B: Rayl

With absorption acoustic energy is converted to:

A: Heat

B: Microbubbles

C: Kinetic energy

D: Decibels

E: Potential energy

A: Heat

The intensity transmission coefficient at the interface between two structures equals 1/100. What is the intensity reflection coefficient?

A: 0/100

B: 99/100

C: 1/100

D: 100/100

E: 49/100

B: 99/100

Which of the following is an example of a Rayleigh scatterer?

A: Renal capsule

B: Arterial wall

C: Red blood cell

D: Bowel gas

E: Femur

C: Red blood cell

Which of the following sound interactions produced the shadows indicated by the arrows on this image?

E: Refraction

In order to display a structure on your sonographic image the sound beam must be reflected at the interface. What is required for sound reflection at the interface of two structures?

A: Oblique incidence at the interface boundary.

B: Temperature differences between the two media.

C: A difference in the acoustic impedance of the media.

D: Different media diameters.

E: Different attenuation coefficients.

C: A difference in the acoustic impedance of the media.

An example of a Specular reflector is:

A: Pericardium

B: Liver parenchyma

C: Red blood cells

D: Ascites

E: Hematoma

A: Pericardium

What system control can you adjust to compensate for the effect of sound attenuation in the body?

A: TGC

B: Dynamic range

C: Frame averaging

D: Depth

E: Line density

A: TGC or Time Gain Compensation

While imaging a cyst you notice shadowing posterior to each lateral border of the cyst. What is the source of the shadows?

A: Redirection of the sound beam at an interface with different propagation speeds and a curved surface.

B: Bending of the sound beam due to different media propagation speeds.

C: Increased attenuation of the sound beam at the borders of the cyst.

D: Lateral misregistration of the cyst due to a multipath artifact.

E: Diffraction of the sound beam resulting in a weakened signal at the lateral borders of the cyst.

B: Bending of the sound beam due to different media propagation speeds.

The algebraic summation of waves leading to patterns of minima and maxima is called:

A: Scattering

B: Interference

C: Absorption

D: Refraction

E: Diffusion

B: Interference

An interaction of echoes that leads to reinforcement rather than to partial or total cancellation is known as:

A: Constructive interference

B: Refraction

C: Destructive interference

D: Autocorrelation

E: Rarefaction

A: Constructive interference

Which phenomenon is associated with a pattern produced by a sound beam after passing through a small aperture?

A: Scattering

B: Absorption

C: Diffraction

D: Interference

E: Diffuse reflection

C: Diffraction

What sound parameter is determined only by the medium?

A: Frequency

B: Period

C: Intensity

D: Propagation speed

E: None of the above

D: Propagation speed

Snell's Law describes:

A: The percentage of reflection at an interface with normal incidence and different densities.

B: The angle of sound transmission at an interface between media having different propagation speeds.

C: The amount of attenuation of sound tissue with depth.

D: The amount of Backscatter from a diffuse reflector.

E: The angle of sound reflection at an interface with oblique incidence and nonspecular reflection.

B: The angle of sound transmission at an interface between media having different propagation speeds.

As a general observation about media in diagnostic sonography sound propagates faster in materials with greater:

A: Compressibility

B: Acoustic impedance

C: Stiffness

D: Refractive index

E: All of the above

C: Stiffness

During the performance of a sonogram you would be most likely to encounter refraction in this view:

A: Specular reflector

B: Curved interface

C: Perpendicular incidence

D: Rayleigh scatterer

E: Refraction is not encountered during an abdominal sonogram

B: Curved interface

You may observe sound attenuation by all of the following EXCEPT:

A: Reflection

B: Scattering

C: Conversion of sound to heat

D: Absorption

E: Compression

E: Compression

When you image sound reflected from a large, smooth interface, you are observing results of:

A: Rayleigh scattering

B: Diffraction

C: Specular reflection

D:Diffusion

E: Refraction

C: Specular reflection

During a sonographic examination of a large vessel, a 45 degree beam-to-vessel angle would be called:

A: Normal incidence

B: Oblique incidence

C: Perpendicular incidence

D: Snell's incidence

E: None of the above

B: Oblique incidence

What occurs when you image a structure with oblique incidence?

A: A very strong reflection will occur since this is the optimal angle for imaging.

B: All of the sound will be reflected due to the poor scanning angle.

C: All of the sound will be transmitted due to the poor scanning angle.

D: The angle of reflection will be oriented away from the transducer resulting in decreased visualization of the structure.

E: The amount of scattering will be reduced with a scanning angle of 45 degrees resulting in a cleaner image with reduced artifactual echoes.

D: The angle of reflection will be oriented away from the transducer resulting in decreased visualization of the structure.

The shadow depicted in this image of a renal stone is primarily a result of the following sound-tissue interaction:

A: Reflection

B: Refraction

C: Destructive interference

D: Cavitation

E: Diffraction

See image for question #64

A: Reflection

Which of the following statements regarding the effect of frequency on Rayleigh scattering is TRUE?

A: The amount of scattering is not affected by frequency.

B: Scattering intensity doubles if frequency is doubled.

C: Doubling the frequency results in halving the scattering intensity.

D: Doubling the frequency results in quartering the scattering intensity.

E: Scattering intensity is proportional to frequency raised to the fourth power.

E: Scattering intensity is proportional to frequency raised to the fourth power.

An echo from which one of the following sound reflectors is most dependent on the angle of incidence?

A: Rayleigh scatterer

B: Diffuse reflector

C: Specular reflector

D: Acoustic scatterer

E: Nonspecular reflector

C: Specular reflector

What term describes the Hyperechoic region (arrow) seen beneath this complex structure?

A: Acoustic enhancement

B: Acoustic shadowing

C: Reverberation

D: Refraction

E: Acoustic impedance

See image for question #67

A: Acoustic enhancement

The Hyperechoic region in the previous illustration results from:

A: Increased acoustic velocity through a fluid-filled structure.

B: Decreased attenuation through a fluid-filled structure.

C: Decreased sound absorption in the region distal to the fluid-filled structure.

D: A high acoustic impedance mismatch between the cyst and adjacent tissue.

E: Bending of the sound beam due to oblique incidence.

See image for question #67

B: Decreased attenuation through a fluid-filled structure.

What determines acoustic impedance?

A: Frequency and propagation speed

B: Frequency and interface size

C: Density and propagation speed of the medium

D: Angle of incidence and media propagation speed

E: Frequency and media density

C: Density and propagation speed of the medium

What system control should you adjust to compensate for sound attenuation with increasing depth?

A: Dynamic range

B: TGC

C: Transmit power

D: Overall Receiver gain

E: Focus position

B: TGC

Diagnostic ultrasound is limited in its diagnostic application to the adult brain because:

A: The speed of sound in the brain is much faster than that in soft tissue resulting in a range artifact.

B: Nearly all of the sound is transmitted at the interface between bone and soft tissue with no reflection to create an image.

C: Diffraction of the sound beam occurs because of the irregular surface of the brain resulting in little transmission of sound through the cranial interface.

D: Bending of the sound beam due to refraction results in a multipath artifact that distorts the image making it non diagnostic at high frequencies.

E: The great acoustic impedance mismatch between the cranium and soft tissue causes most of the sound to be reflected at that interface.

E: The great acoustic impedance mismatch between the cranium and soft tissue causes most of the sound to be reflected at that interface.

Which of the following describe diffuse reflection?

A: The reflected beam is scattered in various directions.

B: The reflected frequency is altered by the Doppler effect.

C: The reflected beam is amplified by the focusing effect of scatterers.

D: The reflected beam is weakened by the large acoustic impedance mismatch at the tissue interface.

E: There is no reflection at a tissue interface because of a disorganized transmit beam.

A: the reflected beam is scattered in various directions.

According to Snell's law the angle of transmission is related to the incident beam angle and:

A: The amount of acoustic impedance mismatch at an interface.

B: The change in frequency that occurs at an interface.

C: One-half of the angle of incidence.

D: The relative speeds of sound in the two media.

E: The percentage of diffraction distal to the interface.

D: The relative speeds of sound in the two media.

Which of the following interactions of sound and tissue decreases the intensity of the transmitted beam?

A: Absorption

B: Reflection

C: Scattering

D: Conversion of sound to heat

E: All of the above

E: All of the above

What is the relationship of frequency to absorption?

A: If frequency is halved, absorption is doubled.

B: If frequency is doubled, absorption is doubled.

C: If frequency is doubled, absorption is halved.

D: If frequency is halved, absorption is quartered.

E: The rate of sound absorption is not frequency dependent.

B: If frequency is doubled, absorption is doubled.

What term is used to describe the reduction in the intensity of sound as it propagates through tissue?

A: Diffraction

B: Refraction

C: Reflection

D: Absorption

E: Attenuation

E: Attenuation

Another term for Nonspecular reflection:

A: Destructive interference

B: Refraction

C: Diffraction

D: Scattering

E: Absorption

D: Scattering

While performing a sonogram, you encounter the following interfaces. Which will produce the weakest reflected signal?

A: Organ parenchyma/fluid

B: Organ parenchyma/air

C: Organ parenchyma/organ parenchyma

D: Organ parenchyma/bone

E: Organ parenchyma/ligament

C: Organ parenchyma/organ parenchyma

During a diagnostic ultrasound examination, you encounter all of the interactions of ultrasound and tissue listed below. Which one will NOT cause a redirection of part of the ultrasound energy?

A: Reflection

B: Scattering

C: Divergence

D: Absorption

E: Refraction

D: Absorption

As you perform a sonogram you switch from a 3.5MHz transducer to a 7.0 MHz transducer to image a superficial structure. Compared to the 3.5MHz transducer what will the 7.0MHz attenuation rate and wavelength be?

A: Double the attenuation rate, one half the wavelength.

B: Double the attenuation rate, double the wavelength.

C: One fourth the attenuation rate, one half the wavelength.

D: One half the attenuation rate, double the wavelength.

E: One half the attenuation rate, one fourth the wavelength.

A: Double the attenuation rate, one half the wavelength.

You are scanning a large mass that is composed primarily of fat. Which of the following are you most likely to encounter?

A: Posterior acoustic shadowing caused by increased attenuation through the fat.

B: Axial misregistration of objects distal to the mass on the screen due to the slower propagation speed through fat.

C: Lateral misregistration of the mass on the screen because of refraction.

D: Total reflection of the sound beam caused by a large acoustic impedance mismatch.

E: Diffraction of the sound beam due to a virtual small aperture through the mass.

B: Axial misregistration of objects distal to the mass on the screen due to the slower propagation speed through fat.

What two conditions must be present to cause refraction of a sound wave?

A: Perpendicular incidence and identical media propagation speeds.

B: Perpendicular incidence and reflector size smaller than one wavelength.

C: Oblique incidence and different media propagation speeds.

D: Oblique incidence and reflector size smaller than one wavelength.

E: Normal incidence and reflector size smaller than one wavelength.

C: Oblique incidence and different media propagation speeds.

The transducer you are using transmits wide-bandwidth pulses whose frequency content is 2-5MHz. Which of the following most correctly describes the reflected echo signals after they have traversed the tissue?

A: The echo signals will be shifted down in frequency due to the increased attenuation of higher frequencies.

B: The echo signals will be of reduced intensity but will have the same frequency content as the transmitted beam.

C: The echo signals will be shifted upward in frequency due to the increased absorption of the lower frequencies.

D: Only the center frequency component of the bandwidth will be reflected back to the transducer.

E: The echo signal frequency content will be identical to that of the transmitted beam.

A: The echo signals will be shifted down in frequency due to the increased attenuation of higher frequencies.

When the sound beam is refracted during a sonographic examination which of the following might you detect on the ultrasound image?

A: Axial misregistration

B: Lateral misregistration

C: Reverberations posterior to a reflector

D: Enhancement of a reflector

E: Electrical interference

B: Lateral misregistration

During production of a sonogram you image the following structures. Which is the MOST attenuating?

A: Blood

B: Bile

C: Soft tissue

D: Calcification

E: Muscle

D: Calcification

What can you do to enhance the visibility of a specular reflector?

A: Scan with the lowest possible frequency.

B: Scan with oblique incidence.

C: Scan with perpendicular incidence.

D: Increase the distance to the reflector.

E: Scan with an incident angle of 45 degrees.

C: Scan with perpendicular incidence.

What interaction of ultrasound and tissue is primarily responsible for imaging the internal structure of organs?

A: Specular reflection

B: Refraction

C: Diffraction

D: Destructive interference

E: Scattering

E: Scattering

What sound-tissue interaction is necessary to form an ultrasound image?

A: Rarefaction

B: Refraction

C: Reflection

D: Diffraction

E: Interference

C: Reflection

For soft tissue one of the factors responsible for determining acoustic impedance is:

A: Attenuation

B: Frequency

C: Absorption

D: Density

E: Amplitude

D: Density

When you image a structure that is a specular reflector the strength of the received signal depends on the following two factors:

A: Difference in acoustic impedance and angle of incidence.

B: Difference in acoustic velocity and interface size.

C: Difference in acoustic velocity and motion of reflector.

D: Angle of incidence and tissue temperature.

E: Bulk modulus and interface size.

A: Difference in acoustic impedance and angle of incidence.

Attenuation of the sound beam increases with increasing:

A: Path length

B: Absorption

C: Frequency

D: Scattering and reflection

E: All of the above

E: All of the above

You are imaging a rounded mass with irregular borders. The mass has a much slower propagation speed than surrounding tissue. What sound tissue interaction will be encountered as the ultrasound propagates through this interface?

A: Refraction

B: Reflection

C: Absorption

D: Scattering

E: All of the above

E: All of the above

You are imaging a structure that is highly attenuating. Which imaging effect do you expect to encounter?

A: Enhancement

B: Increased penetration

C: Shadowing

D: Refraction

E: Increased acoustic speckle

C: Shadowing

When you are educating your patient about the sonographic exam, sound travels through air from your mouth to your patients ears. Which of the following is true regarding the speed of sound travel through air?

A: The speed of sound in air is greater than the speed of light.

B: The speed of sound in air is greater than the speed of sound in soft tissue.

C: The speed of sound in air is not predictable.

D: The speed of sound in air is slower than the speed of sound in soft tissue.

E: The speed of sound in air is equal to the speed of sound in soft tissue.

D: The speed of sound in air is slower than the speed of sound in soft tissue.

In the following illustration, if the propagation speed is unchanged at the interface, which most correctly describes the sound-tissue interaction that will take place when the ultrasound wave strikes the depicted interface?

See image for question #95

A: Specular reflection

B: Scattering

C: Diffraction

D: Refraction

E: None of the above

B: Scattering

You have increased the transmit power while performing a pelvic ultrasound examination. This action increases which of the following?

A: Penetration

B: Acoustic power

C: Image brightness

D: Voltage applied to the transducer elements

E: All of the above

E: All of the above

If sound waves of 3MHz, 5MHz, and 10MHz are transmitted through the same section of anatomy, reflections from which frequency would reach the transducer first?

A: 3MHz

B: 5MHz

C: 10MHz

D: Reflections from all three frequencies would have nearly identical transmit times.

E: It is not possible to predict which will arrive first.

D: Reflections from all three frequencies would have nearly identical transmit times.

What would you change if the image does not show adequate penetration and the far field displays noise instead of tissue?

A: Turn on compound imaging.

B: Move the focal position to a more superficial location.

C: Use an acoustic stand-off pad.

D: Increase TGC.

E: Decrease transmit frequency.

E: Decrease transmit frequency.

For pulsed ultrasound which of the following factors determine the frequency of the sound wave?

A: Pulse Repetition Frequency (PRF)

B: Transmitter frequency

C: Area of the transducer elements

D: Pressure applied to the transducer

E: All of the above

B: Transmitter frequency

You have decreased the acoustic power by -3dB. Which of the following most accurately describes the adjustment?

A: The intensity has been quadrupled.

B: The intensity has been quartered.

C: The intensity has been increased 10 times.

D: The intensity has been halved.

E: The intensity has not been altered.

D: The intensity has been halved.