Ultrasound Applications quiz

1. To eliminate aliasing the best action would be:

a.) Select a higher Doppler frequency.
b.) Place the sample volume at a greater depth.
c.) Decrease the pulse repetition frequency range.
d.) Select a lower Doppler frequency.

You said:
d). Select a lower Doppler frequency.

Correct!

Refer to Eliminate Aliasing for further study.

See: Doppler Effect

2. The maximum Doppler shift occurs at which angle?

a.) Zero degrees
b.) Thirty degrees
c.) Forty-five degrees
d.) Ninety degrees

You said:
a). Zero degrees

Correct!

Refer to Doppler Angle for further study.

See: Doppler Effect

3. The minimum Doppler shift occurs at which angle?

a.) Zero degrees
b.) Thirty degrees
c.) Forty-five degrees
d.) Ninety degrees

You said:
a). Zero degrees

Incorrect!

Refer to Doppler Angle for further study.

See: Doppler Effect

4. What does the cos q component of the Doppler equation solve?

a.) The estimated angle between flow and the vessel wall
b.) The estimated angle between flow and the sample volume
c.) The estimated angle between flow and the sound beam
d.) The estimated angle between flow and skin surface

You said:
c). The estimated angle between flow and the sound beam

Correct!

Refer to Factors Affecting Doppler Angle for additional information.

See: Doppler Effect

5. Which one of the following statements is true?

a.) When red blood cells move toward the transducer the frequency of the reflected wave is less than the frequency produced by the transducer.
b.) When red blood cells move toward the transducer the frequency of the reflected wave is greater than the frequency produced by the transducer.
c.) When red blood cells move toward the transducer the frequency of the reflected wave is the same as the frequency produced by the transducer.
d.) When red blood cells move away from the transducer the frequency of the reflected wave is the same as the frequency produced by the transducer.

You said:
b). When red blood cells move toward the transducer the frequency of the reflected wave is greater than the frequency produced by the transducer.

Correct!

Refer to Factors Affecting Doppler for further study.

See: Doppler Effect

6. The Doppler equation demonstrates that the detected Doppler shift depends upon which one of the following factors?

a.) Velocity of blood flow
b.) Transmit frequency
c.) Angle of insonation
d.) Transmit time

You said:
a). Velocity of blood flow

Incorrect!

Refer to Doppler Effect: Doppler Angle for additional information.

See: Doppler Effect

7. Cos q varies between 0 and 1 as the angle changes from 0° to 90°. When the angle of insonation is 0° the Doppler shift detected is:

a.) Minimum
b.) None
c.) Maximum
d.) Moderate

You said:
c). Maximum

Correct!

Refer to Doppler Angle for further study.

See: Doppler Effect

8. A 5 MHz transducer is used to interrogate a blood vessel with a flow velocity of 100 cm/s using an angle of insonation of 60°. Taking the speed of sound in tissue to be 1540 m/s what would the Doppler shift frequency be?

a.) 1.3 kHz
b.) 3.2 kHz
c.) 5.1 kHz
d.) 1.6 kHz

You said:
d). 1.6 kHz

Incorrect!

Refer to Factors Affecting Doppler for further study.

See: Doppler Effect

9. Which statement best describes a continuous wave Doppler transducer?

a.) A continuous wave Doppler transducer has one crystal.
b.) A continuous wave Doppler transducer detects flow that occurs anywhere within the transmit beam.
c.) A continuous wave Doppler transducer allows unlimited maximum velocity detection.
d.) A continuous wave Doppler transducer gives range resolution information.

You said:
c). A continuous wave Doppler transducer allows unlimited maximum velocity detection.

Correct!

Refer to Continuous Wave Doppler for further study.

See: Doppler Effect

10. Which probe frequency would best detect flow in a superficial vessel?

a.) 2 MHz
b.) 5 MHz
c.) 7 MHz
d.) 10 MHz

You said:
d). 10 MHz

Correct!

Refer to Continuous Wave Doppler for further study.

See: Doppler Effect

11. What is the function of phase quadrature detection?

a.) Amplifies low-level returning echoes.
b.) Filters and amplifies the signal for output to the spectrum analyzer.
c.) Detects the returning echoes.
d.) Determines if the returning signal frequency is higher or lower than the transmitted frequency.

You said:
d). Determines if the returning signal frequency is higher or lower than the transmitted frequency.

Correct!

Refer to Generating a CW Waveform for further study.

See: Doppler Effect

12. The axial dimension of the sample volume is determined by which one of the following?

a.) The shape of the transmitted pulse.
b.) The transmit frequency of the transducer.
c.) The shape of the ultrasound beam.
d.) The length of time the receiving gate is open.

You said:
d). The length of time the receiving gate is open.

Correct!

Refer to Sample Volume for further study.

See: Doppler Effect

13. The frequency at which pulses are sent is known as:

a.) Pulse repetition frequency
b.) Pulse repetition period
c.) Pulse length
d.) Pulse volume

You said:
a). Pulse repetition frequency

Correct!

Refer to Nyquist Limit for further study.

See: Doppler Effect

14. A pulsed wave Doppler system has a pulse repetition frequency of 10 kHz. What is the Nyquist limit?

a.) 2 kHz
b.) 6 kHz
c.) 5 kHz
d.) 3 kHz

You said:
c). 5 kHz

Correct!

Refer to Nyquist Limit for further study.

See: Doppler Effect

15. Range resolution provides what information?

a.) Sample volume depth
b.) Beam focus
c.) Sample volume shape
d.) Pulse detection

You said:
a). Sample volume depth

Correct!

Refer to Pulsed Wave Doppler for further study.

See: Doppler Effect