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MCQ1
1.
Which of the available zoom functions is preferred?
a) pre-processing or write zoom
b) the cine-loop function
c) post-processing or read zoom
d) post-processing curves
2.
Continuous wave (cw) Doppler is useful because:
a) it can measure high blood velocities without aliasing
b) the Nyquist limit is lower than for pulsed Doppler
c) the Doppler signal is easier to interpret because cw Doppler does not detect slow-moving blood
d) the small sample volume means that imaging is not required to guide its use
3.
In ultrasound imaging axial resolution:
a) is worst when a tissue interface is imaged at perpendicular incidence
b) improves when the transducer aperture is increased
c) improves when the depth of focus is reduced
d) is the same at all depths
4.
With regard to the safety aspects of diagnostic ultrasound which of the following statements is true? Diagnostic ultrasound:
a) has been proven to be completely safe
b) produces no known bioeffects in human tissue
c) can be used safely for up to 15 minutes regardless of the TI and MI values
d) can produce harmful effects in human tissue
5.
The maximum Pulse Repetition Frequency (PRF) that the machine can use when imaging is limited by the:
a) depth of penetration
b) transducer aperture
c) focal depth
d) number of lines of sight in the image
6.
In Doppler ultrasound the spectral mirror artifact occurs when:
a) the Doppler angle is 0 degrees
b) the Doppler gain is too low
c) the Doppler angle is 90 degrees
d) the Doppler wall filter is set too low
7.
The axial resolution in an ultrasound image is determined by the:
a) beamwidth
b) slice thickness
c) angle of incidence
d) pulse duration
8.
When a strongly reflective tissue structure is present sidelobes can cause:
a) displacement of the structure in the image to a location deeper than its true position
b) multiple copies of the tissue structure to be displayed at increasing depths
c) axial smearing of the tissue structure in the image
d) multiple copies of the tissue structure to be displayed lateral to its true position
9.
When the ultrasound frequency is increased the Doppler shift:
a) decreases
b) increases or decreases depending on the Doppler angle
c) remains unchanged
d) increases
10.
The purpose of the matching layer in front of the transducer is to:
a) eliminate air from the space between the transducer and the patient
b) absorb energy to minimise the pulse duration
c) ensure the ultrasound travels perpendicularly into the tissues
d) minimise the reflection of ultrasound at the transducer/tissue interface
11.
In laminar flow the velocity profile in a vessel (i.e. the distribution of blood velocities across the lumen of the vessel) is:
a) helical
b) turbulent
c) parabolic
d) plug
12.
Refraction can cause total reflection of the ultrasound at an interface between two tissues when:
a) the acoustic impedance of the second tissue is higher than the acoustic impedance in the first tissue
b) the propagation speed in the second tissue is lower than the propagation speed in the first tissue
c) the acoustic impedance of the second tissue is lower than the acoustic impedance in the first tissue
d) the propagation speed in the second tissue is higher than the propagation speed in the first tissue
13.
The colour that is displayed at each point in a conventional colour Doppler image is determined by the ultrasound machine's estimate of the:
a) Doppler angle
b) acceleration of the tissue and/or blood
c) blood velocity
d) Doppler shift frequency
14.
An ultrasound pulse is attenuated by 40 dB. Its intensity is reduced by a factor of:
a) 40
b) 2000
c) 1000
d) 10000
15.
The wavelength of an ultrasound wave is:
a) the time it takes for a single transmit pulse
b) the time from one transmit pulse to the next
c) the time it takes for a single cycle of ultrasound to occur
d) the distance occupied by a single cycle of ultrasound
16.
Imaging with tissue harmonics:
a) improves image resolution
b) reduces slice thickness artifact
c) reduces sidelobe artifacts
d) all of these
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