SPI Review Questions

The attenuation coefficient in soft tissue is equal to:

One half of the operating frequency (The attenuation coefficient (in dB/cm) is the rate at which sound is attenuated per unit depth. It is equal to one half of the frequency (f/2) in soft tissue.)

Pressure is typically expressed in:

Pascals (Pressure is typically expressed in pascals.)

Which of the following is defined as the number of ultrasound pulses emitted in 1 second? a. Pulse repetition period b. Duty factor c. Pulse repetition frequency d. Spatial pulse length

Pulse repetition frequency (Pulse repetition frequency is defined as the number of ultrasound pulses emitted in 1 second.)

Which of the following describes the amount of refraction that occurs at an interface? a. Bernoulli's law b. Poiseuille's law c. Law of reflection d. Snell's law

Snell's law (Refraction is a redirection of the transmitted sound beam. Snell's law describes the angle of transmission at an interface based on the angle of incidence and the propagation speeds of the two media.)

The frequency of a transducer is 6 MHz. What is the HVL of the transducer?

1 cm

The typical range of frequency for diagnostic ultrasound imaging is:

1 to 20 MHz (The typical range of frequency for diagnostic ultrasound is 1 to 20 MHz.)

Axial resolution is equal to:

1/2 SPL

What is the total amount of attenuation that occurs if a 6.0-MHz sound beam travels through 4 cm of soft tissue?

12 dB (The total amount of attenuation that occurs if a 6.0-MHz sound beam travels through 4 cm of soft tissue is 12 dB.)

All of the following are true of stiffness except: a. It is defined as the ability of an object to resist compression b. Stiffness and propagation speed are indirectly associated c. Increasing stiffness increases propagation speed d. Stiffness may also be referred to as elasticity

Stiffness and propagation speed are indirectly associated (Stiffness and propagation speed are directly related: the stiffer the medium, the faster the propagation speed.)

Which of the following is determined by the sound source and medium? a. Propagation speed b. Frequency c. Period d. Wavelength

Wavelength (Wavelength is determined by both the sound source and the medium.)

Which of the following is described as the distance over which one cycle occurs? a. Pulse duration b. Duty factor c. Period d. Wavelength

Wavelength (Wavelength is distance over which one cycle occurs, or the distance from the beginning of one cycle to the end of the same cycle.)

For maximum transfer for energy to occur, the backing material must have:

an acoustic Z identical to that of the crystal

Dynamic damping is:

an electronic means to suppress the crystal from ringing

The reduction of intensity of the ultrasound beam as it travels through tissue is known as:

attenuation

Which of the following is defined as: the angle at which there is 100% internal reflection and no transmission? a. critical angle b. angle of refraction c. oblique angle of incidence d. angle of reflectivity

critical angle

Which of the following would have the lowest propagation speed? a. Water b. Soft tissue c. Bone d. Lung tissue

d. Lung tissue (which has a propagation speed 660 m/s, has the lowest propagation speed.)

The formula for the Q factor is:

frequency divided by the bandwidth

Use of a higher frequency transducer will result in:

greater attenuation

The angle of incidence between two interfaces is 78 degrees. If the velocity in the second medium is greater than the first medium, then the transmission angle will be:

greater than the incidence angle

More absorption takes place when using a transducer with:

higher frequency

Which of the following is not an advantage of using a piezocomposite material? a. decreased bandwidth b. lower acoustic impedance of crystal so matching layers are more efficient c. increased sensitivity d. increased bandwidth

increased bandwidth

Which of the following is true of the backing layer found in a continuous wave transducer? a. is made of epoxy resin with tungsten b. is located behind the crystal c. is made of air d. utilized to stop the crystal from ringing

is made of air

What is the most common type of man-made material used in diagnostic imaging transducers?

lead zirconate titanate

The property of certain material to create a voltage when they are mechanically deformed is called:

piezoelectric effect

What type of image does a linear segmental array produce?

rectangular image

An increase in pulse repetition frequency would lead to:

An increase in duty factor (An increase in pulse repetition period would lead to an increase in duty factor.)

All of the following are true of power except: a. As amplitude increases, power remains the same b. Power is proportional to amplitude squared c. Intensity is proportional to power d. Power is measured in milliwatts

As amplitude increases, power remains the same (Power decreases as amplitude decreases.)

As a sound wave travels through the human body, the intensity of the sound wave decreases as a result of:

Attenuation, Absorption, Scattering (Attenuation is a decrease in the amplitude, power, and intensity of the sound beam as sound travels through tissue. There are three mechanisms of attenuation: absorption, reflection, and scattering.)

is described as the ability of an object to resist compression and relates to the hardness of a medium?

stiffness (Stiffness is the ability of an object to resist compression and relates to the hardness of a medium)

Which of the following would have the highest propagation speed? a. Air b. Bone c. Soft tissue d. Water

Bone (Bone, which has a propagation speed of 4080 m/s, has the highest propagation speed.)

Ultrasound crystals vibrate in the

thickness mode

Areas of high pressure and density are referred to as:

Compressions (Areas of high pressure and density are referred to as compression.)

As imaging depth increases, the pulse repetition frequency must:

Decrease (As imaging depth increases, the PRF decreases.)

The percentage of time that the ultrasound system is producing pulses of ultrasound describes the:

Duty factor (The duty factor is the percentage of time the ultrasound system is producing a sound.)

As imaging depth increases, pulse repetition period:

Increases (As imaging depth increases, the pulse repetition period increases.)

If pulse repetition frequency increases, then the duty factor:

Increases (If the pulse repetition frequency increases, the duty factor increases.)

Density and propagation speed are:

Inversely related (Density and propagation speed are inversely related.)

All of the following are true of wavelength except: a. It is determined by both the medium and the sound source b. It is equal to the period divided by the frequency c. It is inversely related to frequency d. It is directly related to period

It is equal to the period divided by the frequency (Wavelength is equal to the propagation speed divided by the frequency.)

Density is typically measured in:

Kilograms per centimeter cubed (Density is typically measured in kilograms per centimeter cubed.)

Micro denotes:

Millionth (Micro denotes millionth.)

Spatial pulse length can be calculated by:

Multiplying the number of cycles times the wavelength (Spatial pulse length equals the number of cycles in the pulse multiplied by the wavelength.)