T/F Flashcards
The pulse duration can be altered by increasing the depth of the image.
False, the sonographer CANNOT change the PD
Absorption is the greatest contributor to attenuation in tissue.
True
Speculator reflectors occur when sound beam hits a small, rough interface at 90 degrees.
False, large smooth surface at 90 degrees
Speculate reflectors are highly angle dependent.
True
When sound strikes an interface with an oblique angle of incidence, the transmitted beam angle will equal the incident angle only if the propagation speed of medium one is faster than medium two.
False, the propagation speeds must be identical
In phase waves undergo constructive interference to make a smaller, stronger wave.
False, the amplitudes are added together to make one big wave
Sensitivity is the ability of a system to display weak echoes.
True
Q factor relates to the resolution of the image, so a high Q factor is better than a low one.
False, Q factor is related to purity of the sound beam
High Q factor means a purer beams which means a narrow bandwidth, longer pulse length and reduced image quality
Array transducers steer the beam electronically, either in a sequential pattern or a phased pattern.
True
Linear array transducers have the elements arranged in a line and are fired one at a time in a sequence.
False, they are fired in small groups in a sequence.
Ex: (1-2-3) …. (4-5-6)
Curvilinear array transducers are best for abdominal, gynecology, and obstetrics imaging.
True
All transducers electronically focus the beam.
False, mechanical transducers have a fixed focus
Pulse wave transducers have two crystals, one to transmit sound and one to receive.
False, continuous wave transducer have two crystals
An axial resolution of 0.4 mm is better than 0.2 mm.
False, 0.2 mm is better axial resolution because two reflectors could be that close to each other and you’d still be able to tell the difference between them
The beam former controls the timing of signals sent to individual elements for steering and focusing of the beam.
True
Increasing the receiver gain will increase the output power.
False
When using tissue harmonic imaging, the machine processes the fundamental frequency and the second harmonic.
False, the fundamental frequency is filtered out
Harmonic signals are produced by the patient, not the transducer.
True
Rectification turns positive voltages into negative voltages.
False, negative to positive
It is better to have more shades of grays than more pixels.
False
Read zoom is a preprocessing function that enlarges the image by magnifying the pixels.
False, it does magnify the pixels but it is a post processing function
Comet tail is a type of refraction artifact.
False, reverberation artifact
Comet tail artifact is caused by sound interacting with small air bubbles.
False, comet tail is caused by small structure like surgical clips or Adenomyomatosis
Ring down caused by sound making air bubbles vibrate.
True.
With mirror image artifact, the duplicate object will always appear closer that the actual structure.
False, it appears deeper
Spatial compounding eliminates edge shadowing which reduces margin delineation.
False, improves margin delineation
Side lobes occur with array transducers and grating lobes occur with single element transducers.
False, side is single and grating is array
All artifacts are negative and should be eliminated.
False, shadowing and enhancement can be beneficial in differentiating between benign and malignant processes
Coded excitation improves signal to noise ratio.
True
DICOM is the standard for storing in imaging systems.
False, it is the standard for data exchange among imaging systems
Blood flows to higher pressure areas of vessels.
False, to low pressure areas
The fastest velocity is found in the boundary layer of laminar flow.
False, fastest velocity is in the center
Boundary layer is region of stationary blood cells
Turbulent flow is ALWAYS a sign of disease.
False, it may occur in tortuous vessels, in dips (carotid bulbs) and if sample gate is too close to the side of the wall
Vector array transducers commonly produce a sector image shape.
False, phased array transducers do
There are two forms of cavitation: inertial and normal.
False. Inertial, transient and normal are the same. The correct answer is stable and normal
