Doppler Signal processing derives the:

A. Doppler Shift

B.Reflected frequency

C. Pulse Repetition frequency

D.Transmitting frequency

E.Oscillator frequency

In pulsed Doppler ultrasonography the red blood cell acts mainly as:

A. An ultrasonic field.

B. A small reflector.

C. An absorbent field.

D. A sound source.

E. An attenuator.

The reflected Doppler signal contains how many frequencies?

A. Only one.

B. It depends on the transducer's central frequency.

C. It depend on the distribution of reflector velocities.

D. It depends on the speed of sound.

E. It depends on the tissue attenuation.

When an ultrasound reflector is moving away from a source the reflected frequency may be which of the following:

A. Twice the incident frequency.

B. 3 times the incident frequency.

C. Equal to the incident frequency.

D. 0.1% higher than the frequency of the transducer.

E. 0.1% lower than the frequency of the transducer.

The largest Doppler shift occurs when the beam of ultrasound intersects the vessel at a:

A. 90 degree angle.

B. 45 degree angle.

C. 0 degree angle.

D. 30 degree angle.

E. 15 degree angle.

Movement toward an ultrasound beam produces an upward shift in the reflected frequency.  Circuits within a directional Doppler would detect this as:

A. Continuous flow.

B. Flow towards the ultrasound transducer.

C. Pulsed flow.

D. Flow away from the ultrasound transducer.

E. Pulsatile flow.

The one factor in the Doppler equation which is unknown when using continuous wave handheld pencil probe transducers is:

A. The angle of incidence.

B. The transmitting frequency.

C. The Doppler frequency.

D. The speed of sound in soft tissue.

E. The received frequencies.

A pulse repetition frequency (PRF) less than twice the Doppler frequency will result in:

A. Cavitation.

B. Aliasing.

C. Increased intensity.

D. Decreased intensity.

E. Increased attenuation.

Using quadrature detection, the instrument displays directional information using the two output signals by noting their:

A. Wavelength differences.

B. Strength differences.

C. Phase differences.

D. Intensity differences.

E. Zero detection differences.

The doppler frequency shift heard on a speaker or seen on a spectrum analyzer is the difference between the transmitted frequency and the:

A. Doppler probe frequency.

B. Received frequency.

C. Transmitted intensity.

D. Speed of sound through tissue.

E. Angle of incidence.

While using a continuous wave Doppler instrument to study an artery, all of the following are likely to be potential sources of error EXCEPT:

A. Oblique insonation of the artery.

B. Calcified tissue wall.

C. Simultaneous insonation of an artery and a vein.

D. A 45 degree angle of incidence.

E. A low high-pass filter.

Which of the following contribute to the inherently low doppler signal level from blood?

A. The transmitted power.

B. Angle of Doppler beam incidence (with respect to blood flow path.

C. The strong reflection coefficient of red blood cells to ultrasound.

D. The low backscatter level of red blood cells to

    ultrasound.

E. A and C.

D. The low backscatter level of red blood cells to

    ultrasound.

The conversion of the Doppler signal into an analog signal that displays the mean frequency as a function of time is usually performed by a:

A. Unidirectional Doppler.

B. Bidirectional Doppler.

C. Zero-crossing detector.

D. Fast Fourier transformer

E. Zero-FFT analysis

The signal output from a zero-crossing detector is:

A. An analog voltage proportional to the number of zero-crossings per unit of time.

B. An analog voltage proportional to the depth of the reflectors.

C. A digital signal proportional to the strength of the Doppler signal.

D. An analog voltage proportional to the number of red blood cell density alterations.

E. A digital signal proportional to the depth of the reflectors.

Waveforms generated by a zero-crossing detector show:

A. Maximum instantaneous Doppler frequency.

B. Root mean square Doppler frequency.

C. The lowest Doppler frequency.

D. Peak Doppler shift frequencies.

E. Low amplitude Doppler signals only.

Spectral analysis is often referred to as a process of:

A. Separating a signal into electrical components which define the greatest velocity flow.

B. Combining alll frequencies received from a Doppler signal and rearranging them to allow max display of  the flow velocities.

C. Separating a signal into its individual frequency components.

D. Separating a signal into different amplitude components.

E. Creating an analog signal from the Doppler shifts.

C. Separating a signal into its individual frequency components.

Spectral analysis displays which of the following components of the Doppler signal:

A. Amplitude, frequency, capacitance.

B. Capacitance, time, frequency.

C. Time, amplitude, voltage.

D. Voltage, capacitance, frequency.
E. Amplitude, time, frequency.

E. Amplitude, time, frequency.

The frequencies displayed by Doppler spectral analysis do NOT depend on:

A. Angle of incidence.
B. Red blood cell count.

C. Speed of ultrasound in soft tissue.

D. Operating frequency of the transducer.

E. Velocity of blood flow.

The fast Fourier transform does NOT allow the technologist to:

A. Perform Fourier analysis.

B. Perform frequency spectrum analysis.

C. Perform velocity spectrum analysis.

D. Detect spectral broadening.

E. Measure velocities without angle correction.

A unique advantage of FFT (fast Fourier transform) spectral analysis over zero-crossing analog analysis is:

A. FFT analysis avoids the problems of aliasing, common in analog detection systems.

B. FFT extracts and displays the separate component frequencies representing the blood velocity profile.

C. Calculation of flow velocity can be determined only by utilizing FFT
analysis.

D. FFT spectral analysis cannot calculate flow acceleration at low frequency shift values; it offers no clinical advantage.

E. FFT mathematically provides an analog envelope-analogous to the
Doppler shift.

B. FFT extracts and displays the separate component frequencies representing the blood velocity profile.

Which one of the following statements is TRUE regarding fast Fourier transform spectral analysis?

A. It is used to analyze the individual frequency components of a composite Doppler frequency shift spectrum.

B. It is responsible for the phenomenon of signal aliasing in extreme frequency shift states.

C. Simultaneous, separate display of forward and reverse flow components can confuse the system, rendering a frequency shift pattern which is artificially blunted.

D. It is only accurate when used in conjunction with continuous wave, or pulsed Doppler systems using a large sample volume gate.

E. It is less accurate than analog waveform analysis for low flow states.

A. It is used to analyze the individual frequency components of a composite Doppler frequency shift spectrum.

The auditory Doppler signal is the result of:

A. Frequency changes in the reflected ultrasound beam produced by acoustical impedance changes at different tissue layers.

B. Frequency changes in the reflected ultrasound beam produced by stenosis within the vessel.

C. Frequency changes in the reflected ultrasound beam produced by movement of the red blood cells through the vessel.

D. Algorithms derived from the computer based on time/ depth processing of the reflected ultrasound beam.

E. The reversed Doppler frequency.

C. Frequency changes in the reflected ultrasound beam produced by movement of the red blood cells through the vessel.

In continuous wave Doppler ultrasound, which of the following would NOT produce a Doppler frequency shift?

A. Movement of the probe on the skin above the vessels studied.

B. Vessel wall motion.

C. Movement of an intimal flap.

D. Movement of a thrombus within the vessel.

E. Slow movement that falls below the detection threshold.

The frequency of the Doppler signal may be influenced by all of the following EXCEPT:

A. The transducer frequency.

B. The angle of the ultrasound beam with respect to the movement path of the target.

C. The direction of travel of the target with respect to the ultrasound transducer.

D. The velocity of the moving target.

E. The tissue through which the ultrasound is traveling.

Aliasing is:

A. The act of registering at a hotel under an assumed name.

B. A misleading upside down presentation of Doppler flow data.

C. The waveform display seen when the Doppler gain is overdriven.

D. The waveform display seen when the continuous wave Doppler beam overlaps an artery and a vein.

E. Using the incorrectly sized Doppler transducer.

Aliasing can occur in:

A. Pulsed Doppler systems.

B. Either pulsed or continuous wave Doppler systems.

C. Duplex imaging systems.

D. Plethysmographs.

E. Continuous wave Doppler systems.

The pulse repetition frequency (PRF) is:

A. The transmitted frequency of the Doppler ultrasound beam.

B. The rate at which the continuous wave Doppler ultrasound transducer is stimulated.

C. The speed at which the sound pulse travels through a given tissue structure.

D. The number of times per second a pulsed Doppler transducer is stimulated.

E. The rate of Doppler frequency shifts.

Aliasing will NOT occur in pulsed Doppler if the frequency shift is:

A. Equal to that of the system's pulse repetition frequency.

B. Equal to 60 percent of the system's pulse repetition frequency.

C. Equal to 40 percent of the system's pulse repetition frequency.

D. Equal to two times the system's pulse repetition frequency.

E. Three times the system's pulse repetition frequency.

Using a pulsed Doppler transducer of 5 MHz with a pulse repetition frequency (PRF) of 15 kHz, which of the following frequency shifts would produce aliasing?

A. 1.5 kHz.

B. 5 kHz.

C. 6.25 kHz.
D. 7 kHz.

E. 8.8 kHz.

Zero-crossing detector systems provide analytic information on the Doppler signal:

A. Mean frequency.

B. Spectral bandwidth.

C. Phase shift.

D. Very low flow velocities below 10 cm/sec.

E. All of the above.

In using spectral analysis with a continuous wave Doppler instrument, which differences would you expect when compared to pulsed Doppler recordings of the same vessel?

A. Higher peak velocity.            /

B. Opening up of the spectral window.

C. Filling in of the spectral window.

D. Lower peak velocity.

E. No difference at all.

All of the following must be known to calculate the velocity of blood by the Doppler technique EXCEPT:

A. Beam/vessel angle of incidence.

B. Transmitted ultrasound frequency.

C. The shifted frequency of the returning ultrasound.

D. The arterial or venous blood flow rate.

E. The speed of ultrasound in tissue.

The cosine of 90 degrees is:

A. 0.0000.

B. 0.4545.

C. 0.5000.

D. 0.7070.

E. 1.0000.

Simultaneously, two pure musical notes are played constantly, one at 60 Hz, the other at 80 Hz. Which statement describes the presentation of these on a spectrum analyzer's display of frequency (vertically) versus time (horizontally)?

A. One straight line at 140 Hz.

B. One sine wave centered at 140 Hz.

C. Two straight lines, one at 60 Hz and the other at 80 Hz.

D. Two sine waves, one centered at 60 Hz and the other centered at 80Hz.

E. One sine wave centered at 70 Hz.

The Doppler frequency shift:

A. Is independent of the frequency of the transducer.

B. Is proportional to the frequency of the transducer.

C. Is greater for a 5 MHz transducer than to a 7.5 MHz transducer.

D. Is independent of the direction of flow.

E. Cannot be in the kHz range.

In the Doppler (FFT) fast Fourier transform:

A. Flow turbulence does not affect spectral broadening.

B. The velocity profile does not affect spectral broadening.

C. The angle of insonation affects spectral broadening.

D. The size of the sample volume does not affect spectral broadening.

E. The size of the sample volume affects spectral broadening.

The piezoelectric crystal transforms:

A. Voltage signals into pressure signals but not pressure signals into voltage signals.

B. Pressure signals into voltage signals but not voltage signals into pressure signals.

C. Voltage signals into pressure signals or pressure signals into voltage signals.

D. Pressure signals into magnetic signals and magnetic signals into pressure signals.

E. Pressure signals into magnetic signals but not magnetic signals into
pressure signals.

Which of the following statements is true about an ultrasonic wave?

A. Frequency is directly proportional to the period.

B. Period and frequency are independent of each other.

C. Period and frequency have the same unit of measurement.

D. The product of the period and the frequency is constant.

E. Period is directly proportional to frequency.

Assuming that the velocity of propagation of a sound wave is constant, the:

A. Wavelength is directly proportional to the frequency.

B. Wavelength and the frequency are unrelated.

C. Wavelength is inversely proportional to the frequency.

D. Product of the frequency and the wavelength varies with frequency.

E. Wavelength and the frequency have the same unit of measurement.

If two sinusoidal waves of the same amplitude are added together:

A. If the two waves are in phase, the amplitude of the resulting wave will be equal to the amplitude of the two individual waves.

B. If the two waves are 180 degrees out of phase, the amplitude of the resulting wave is zero.

C. The amplitude of the resulting wave is independent of the relative
phase of the two waves.

D. If the two waves are in phase, the amplitude of the resulting wave is zero.

E. If the two waves are 90 degrees out of phase, the amplitude of the resulting wave is zero.

Which statement is true about the fast Fourier transform (FFT)?

A. It is not applicable to Doppler signals.

B. It is applicable to Doppler signals but not to other echo signals.

C. It is applicable only to color Doppler signals.

D. It is a computational algorithm that speeds up calculation of the
frequency components of complex waveforms.

E. It is applicable to electronic signals but not to ultrasonic wave amplitudes.

The pulse repetition frequency (PRF) directly affects the:

A. Speed of real-time events.

B. Highest Doppler frequency detectable without aliasing.

C. Number of lines per frame.

D. Amplitude of ultrasonic signals from the same depth.

E. Lateral resolution.

Based on the velocity of propagation of ultrasound in soft tissue, it takes about:

A. 13 microseconds to receive echoes from a tissue interface 2 cm away from the transducer.

B. 26 microseconds to receive echoes from a tissue interface 2 cm away from the transducer.

C. 39 microseconds to receive echoes from a tissue interface 2 cm away from the transducer.

D. 52 microseconds to receive echoes from a tissue interface 2 cm away from the transducer.

E. 55 microseconds to receive echoes from a tissue interface 2 cm away from the transducer.

B. 26 microseconds to receive echoes from a tissue interface 2 cm away from the transducer.

Regarding piezoelectric transducers, the term piezo means:

A. Power.

B. Voltage.

C. Pressure.

D. Oscillation.

E. Displacement.

A short burst of electrical energy makes a piezoelectric
transducer:

A. Transmit a short burst of mechanical energy.

B. Reflect the electrical energy.

C. Transmit a short burst of electrical energy.

D. Heat up the tissue.

E. Reflect the mechanical energy.

The range equation relates:

A. Time and frequency.

B. Time and distance.

C. Distance and wavelength.

D. Speed and impedance.

E. Spatial peak and average.

A pulse of sound is transmitted from a transducer into a phantom. It strikes a reflector 5 cm down. The echo arrival time is 65 microseconds. What would be the echo arrival time for a reflector 10 em deep in the same phantom?

A. 32.5 microseconds.

B. 65 microseconds.

C. 130 microseconds.

D. 650 microseconds.

E. 1300 microseconds.

A small increase in ultrasound frequency would NOT necessarily affect the:

A. Pulse duration.

B. Sound wave period.

C. Wavelength.

D. Resolution.

E. Pulse repetition frequency.

An increase in the pulse repetition frequency will cause a decrease in the:

A. Sound wave frequency.

B. Sound wave period.

C. Pulse duration.

D. Pulse repetition period.

E. Half wavelength.

The duty factor is NOT affected by:

A. Speed of sound.

B. Pulse damping.

C. Pulse repetition frequency.

D. Pulse duration.

E. Period between pulses.

Increasing the output power by 9 dB increases the sound intensity by:

A. 4 times.

B. 6 times.

C. 8 times.

D. 27 times.

E. 16 times.

Increasing the overall gain setting affects signals in the:

A. Transducer.

B. Transmitter.

C. Receiver.

D. Patient.

E. Ultrasonographer.

The time gain (also called depth gain or swept gain) compensation (TGC) control aids the operator in compensating for sound beam:

A. Velocity.

B. Refraction.

C. Transmission.

D. Dynamic aperture.

E. Attenuation.

The compression control allows the operator

to adjust the:

A. Amplification.

B. Demodulation.

C. Dynamic aperture.

D. Dynamic range.

E. Frequency range.

The component with the widest dynamic range is the:

A. Receiver.

B. Memory.

C. Display monitor.

D. Hard copy.

E. Post-processing circuits.

In an A-mode display, spike height represents:

A. Distance between reflectors.

B. Distance from the transducer.

C. Echo arrival time.

D. Echo amplitude.

E. Brightness.

In a typical M-mode display, the horizontal axis depicts:

A. Echo amplitude.

B. Distance.

C. Dot brightness.

D. Acoustic interface.

E. Time.

Which mode does NOT represent echo amplitude by dot brightness on the display?

A. A-mode.

B. B-mode.

C. M-mode.

D. C-mode.

M-mode is NOT able to display:

A. Echo amplitude.

B. Distance from the transducer.

C. Time.

D. Cross-sections.

E. Motion.

Which information is NOT relevant to the positioning of echoes on a display monitor during B-mode imaging?

A. Beam angle.

B. Echo amplitude.

C. Echo arrival time.

D. Speed of sound.

B. Echo amplitude.

The purpose of introducing a water path intothe

design of an ultrasound scanner was to:

A. Obtain a higher frame rate.

B. Increase patient comfort.

C. Improve resolution of deep structures.

D. Improve resolution of superficial structures.

E. Decrease resolution of the deep structures.

Advantages of real-time instruments over manual static scanners do NOT include:

A. Higher frame rates.

B. Shorter examination time.
C. Depiction of motion.

D. Larger fields of view.

The primary factor limiting frame rates in medical ultrasound is the:

A. Transducer frequency.

B. Manufacturing cost.

C. Number of memory bits.

D. Speed of the technologist.

E. Speed of sound.

An ultrasound device transmits 100 beam lines per frame. With the depth set at 10 cm, what is the maximum obtainable frame rate?

A. 77 frames per second.

B. 154 frames per second.
C. 7700 frames per second.

D. 77,000,000 frames per second.

E. 1,540,000 frames per second.

Increasing the depth of the imaging field       ___the maximum frame rate:

A. Increases.

B. Decreases.
C. Doubles.

D. Triples.

E. Does not affect.

Which one of these examples is NOT a model

for the Doppler effect:

A. Running past a loudspeaker playing music.

B. Listening to a speeding car pass you.

C. Listening to the whistle of a moving train.

D. Running against the waves in the ocean.

E. Listening to music in a jet airplane.

E. Listening to music in a jet airplane.

The Doppler frequency shift does not depend on:

A. Transducer frequency.

B. Blood velocity.

C. Ultrasound attenuation.

D. Angle of insonation.

E. Propagation velocity.

If the transducer frequency is falsely estimated to be 5 MHz when in reality it is 5.5 MHz (10 percent change), the blood velocity estimate will be:

A. Decreased by 10 percent.

B. Unaffected by transducer frequency.
C. Equal to the actual velocity.

D. Lower than the actual velocity.

E. Higher than the actual velocity.

The Doppler angle yielding the highest Doppler shift is:

A. 60 degrees.

B. 0 degrees.

C. 45 degrees.

D. 72 degrees.

E. 50 degrees.

Which of the following best describes structures in the body that contribute to the Doppler signal?

A. Moving blood only.

B. Vessel walls only.

C. Blood that is moving at a 90 degree angle relative to the ultrasound beam.

D. Any moving reflector in the path of the ultrasound beam that has a velocity component.

E. Moving reflectors and nearby stationary reflectors.

Doppler instruments with stereo audio signals allow for
differentiation between forward and reverse flow in which of the following ways?

A. Triphasic sound is heard in both earphones.

B. Monophasic sound is heard in both earphones.

C. Reverse sound is heard in both ear phones.

D. Forward flow is heard in one earphone and reverse flow is heard in the other earphone.

E. Forward flow is heard in both earphones.

The common duplex spectral display with time as the horizontal axis has:

A. Power as the vertical axis and number of reflectors as brightness
(signal amplitude).

B. Number of reflectors in the vertical axis and velocity as brightness.

C. Velocity as the vertical axis and number of reflectors as brightness
(signal amplitude).

D. Intensity of the signal as the vertical axis and number of reflectors as the brightness (signal amplitude).

E. Power as the vertical axis and intensity as brightness.

If the sample size increases, the total spectral power:

A. Increases and the spectral broadening decreases.

B. Remains the same and the spectral broadening decreases.

C. Remains the same and the spectral broadening increases.

D. Decreases and the spectral broadening increases.

E. Increases and the spectral broadening increases.

With double aliasing, the:

A. Positive high velocities become negative high velocities.

B. Positive high velocities become positive low velocities.

C. Positive high velocities become negative low velocities.

D. Negative low velocities become positive high velocities.

E. Negative high velocities become positive high velocities.

A technical cause of aliasing may be:

A. Insonating at 30 degrees rather than at 60 degrees.

B. Using a 5 MHz transducer rather than a 10 MHz transducer.

C. Using 16 frames per second rather than 12 frames per second.

D. Insonating blood that is moving at 50 rather than 100 cm/s.

E. To assume propagation velocity of 1540 m/s.

The continuous wave Doppler device:

A. Has a duty cycle of 50 percent.

B. Can identify the depth of origin of the signal.

C. Has a small sample volume.

D. Cannot measure high velocities.

E. Does not alias.

The pulsed Doppler instrument:

A. Has a duty cycle of 50 percent.

B. Relates echo arrival time to vessel depth.

C. Receives a signal that is independent of sample volume size.

D. Does not provide information on depth of origin of the Doppler signal.

E. Does not alias.

While continuous wave Doppler instruments are less complex, pulsed Doppler alone allows for:

A. Depth location.

B. Frequency shift.

C. Blood flow determination.

D. Spectral analysis.

E. Directional separation.

When pulsed Doppler is being used, which characteristic(s) is(are) NOT valid determinants of the shape and size of the sample volume?

A. The transmitted pulse length.

B. The beam width.

C. The slice thickness.

D. The gate duration.

E. The spectral scale range.

Which of the following statements is FALSE regarding continuous wave Doppler?

A. Differentiation of signals from different depths cannot be done.

B. Vessels which lie above or below the focal depth of the transducer
cannot be studied.

C. The two transducer elements are always in operation.

D. Aliasing can occur at frequency shifts above a range, specific to the
instrumentation used.

E. The instrument may be used to detect vasculogenic impotence.

Why does aliasing NOT occur in continuous wave Doppler systems?

A. Because of the higher designated frequencies which can be used with continuous wave Doppler.

B. Because of the lower frequencies received by continuous wave Doppler instruments.

C. Because the transducer is constantly transmitting ultrasound which faithfully recreates the constantly changing flow velocity patterns within the vessel.

D. Because of the inherently greater frequency shift produced by the
relatively stronger broadcast signal.

E. Because the sampling of the entire vessel averages the flow velocities to minimize the peak systolic velocity and more faithfully reproduces the true flow velocity patterns in the vessel.

The pixel color on a color flow velocity image represents:

A. Amplitude of echoes from blood.

B. Blood velocity, independent of angle.

C. The flow direction.

D. Movement of blood and tissue.

E. Movement of blood but not tissue.

Doppler color flow imaging:

A. Is based on the Doppler effect.

B. Is not affected by the direction of blood flow.

C. Is affected by direction of blood flow.

D. Is not affected by aliasing.

E. Eliminates angle correction in velocity calculations.

In comparing continuous wave Doppler with pulsed Doppler:

A. Both discriminate signals from different depths.

B. A continuous wave Doppler is a pulsed Doppler with a duty cycle of
50 percent.

C. If both Doppler devices are transmitting signals with the same
amplitude, a continuous wave Doppler transmits less energy to the
tissue than a pulsed Doppler.

D. The Doppler shift is different for continuous and pulsed Doppler
instruments transmitting at the same frequency.

E. Continuous wave Doppler has a duty cycle of 1.00.

With Doppler ultrasound, if the echo frequency at the transducer is lower than the transmitted frequency, we can conclude that the reflector is ____                the transducer:

A. Moving toward.

B. Moving away from.

C. Moving perpendicular to.

D. Not moving compared to.

E. Moving at twice the frequency away from.

If blood is flowing toward a 2 MHz transducer, you would expect the frequency of the Doppler shift to be__________ 2 MHz:

A. Slightly greater than.

B. Slightly less than.
C. Much greater than.

D. Much less than.

E. Equal to.

D. Much less than.

The amplitude of scattered echoes from red blood cells is LEAST affected by:

A. Reflector velocity.

B. Attenuation of soft tissue.
C. Transducer frequency.

D. Hematocrit.

A peak Doppler shift of 4 kHz is detected in a large artery. If the peak velocity in the vessel were to double, the detected peak Doppler shift would be:

A. 2kHz.
B. 4kHz.
C. 8 kHz.
D. 16kHz.
E. 32 kHz.

A 5 MHz transducer detects a peak Doppler shift of 12 kHz in an artery. With a 2.5 MHz transducer, the same vessel would be expected to produce a peak Doppler shift of:

A. 6kHz.
B. 12 kHz.
C. 24 kHz.

D. 10 kHz.

E. 18 kHz.

An artery is interrogated with the ultrasound beam at an angle of 40 degrees. A peak Doppler shift of 3 kHz is detected. If the beam angle is increased to 60 degrees, you would expect the peak Doppler shift to be ____ 3kHz:

A. Greater than.

B. Less than.

C. Equivalent to.
D. Double.

A small error in the estimation of the Doppler angle will result in the largest velocity miscalculations when the Doppler angle is:

A. 0 degrees.

B. 10 degrees.
C. 45 degrees.

D. 80 degrees.

E. 60 degrees.

A Doppler device without a spectrum analyzer CANNOT display:

A. Peak velocity.

B. Mean velocity.

C. Velocity changes over time.

D. The distribution of reflector velocities.

Spectral broadening in the Doppler display is LEAST likely to result from:

A. Long sample volume.

B. Turbulent flow.

C. High wall filter setting.
D. Very high gain.

Gating determines the:

A. Transmitting frequency.

B. Doppler frequency.

C. Sample volume length along the beam direction.

D. Sample volume width, perpendicular to the beam direction.

C. Sample volume length along the beam direction.

How often a Doppler signal is sampled is determined by the              _ frequency:

A. Transmitted.

B. Received.

C. Doppler shifted.

D. Pulse repetition.

E. Heartbeat.

If a pulsed Doppler device is operating at a PRF of 6000/s, what is the maximum Doppler frequency that can be accurately detected?

A. 3kHz.

B. 6kHz.

C. 12 kHz.
D. 18kHz.
E. 24 kHz.

A. 3kHz.

Aliasing occurs at lower Doppler frequencies when the sample volume is:

A. Moved toward the transducer.

B. Moved away from the transducer.

C. Increased in width.

D. Operated in continuous wave mode.

Methods of compensating for aliasing do NOT include:

A. Transmitting at a higher frequency.

B. Adjusting the spectral baseline.

C. Increasing the velocity scale range.

D. Switching to continuous wave Doppler.

Range discrimination is POOREST with:

A. M-Mode.

B. Continuous wave Doppler.

C. Pulsed Doppler.

D. Color Doppler.

The highest velocities can be accurately evaluated by:

A. Real-time B-mode.

B. Pulsed Doppler.

C. Continuous wave Doppler.

D. Color Doppler.

E.M-mode.

Increasing the color packet size results in:

A. Better velocity estimates, higher frame rates.

B. Better velocity estimates, lower frame rates.

C. Worse velocity estimates, higher frame rates.

D. Worse velocity estimates, lower frame rates.

E. Better velocity estimates, unchanged frame rates.

The term "variance" refers to:

A. Peak velocity.

B. Mean velocity.

C. Velocity range.

D. Velocity threshold.

E. Frequency threshold.

The most accurate display of the velocity distribution at a single sample gate occurs with:

A. Continuous wave Doppler.

B. Pulsed Doppler.

C. Color Doppler.

D. C-mode.

E. B-mode.

A system that presents a B-mode image and a velocity spectral waveform in real time is commonly called a(n):

A. Color flow scanner.

B. M-mode scanner.

C. Echo Doppler.

D. Ultrasonic imager.

E. Duplex scanner.