What is the term for an area of the image where there is no returning echoes (black)
hypoechoic
anechoic
echogenic
What are the advantages of ultrasound?
Good soft tissue information, real time, no ionising radiation and accurate measure of structures
Can carry out blood studies, relatively quick and cost effective, highly operator dependant, image interpretation
Can carry out blood studies, ionising radiation, real time and accurate measure of structures
Highly operator dependant, accurate measure of structures, image interpretation, highly operator dependant
True or False. The frequency of ultrasound is below the human hearing?
True
False
What frequency range is used for ultrasound?
20-20,000Hz
1-20MHz
20-40MHz
1-20Hz
What are the four basic components of ultrasound equipment?
Transducer, monitor for display, housing with electronics and controls, coupling gel
Transducer, timing device, housing with electronics and controls, recording device
Transducer, monitor for display, housing with electronics and controls, recording device
Transducer, timing device, housing with electronics and controls, coupling gel
When was the piezoelectric effect discovered by Jacques and Pierre Curie?
1980
1950
1850
1880
Name the two basic waves by which energy can be transmitted from one point to another
electromagnetic and mechanical waves
sound and mechanical waves
True or False? Light and X-rays are electromagnetic waves
What are mechanical waves described as?
propagation of energy through a medium by cyclic pressure variations
distinguished by energy, frequency and wavelength
Man-made forces changing the frequency of the wave
similar to ocean waves
Which of the following deformable elastic mediums can be used for propagation?
Air
Water
Soft tissue
All of the above
What is the frequency of a wave?
The difference between maximum value and equilibrium value
Length of one cycle
The number of cycles that occur per second
The speed of the soundwave as it passes through the tissue
True or false? With heavier molecules the sound transmits with faster velocity
True or False? With more compressable materials (eg air) the sound transmits at a lower velocity
What part of the beam affects the strength of the echo?
intensity
transducer
shadowing
placement
What is the change in direction of an ultrasound beam when it crosses a boundary at an angle?
Rarefraction
Attenuation
Beam angling
Focusing
What do the attenuation processes include?
absorption
Divergence
Scattering
Reflection
Which of the following has the lowest attenuation coefficient?
Blood
Lung
Soft Tissue
Brain
Absorption
Is a result of internal friction forces
Is when ultrasound energy is converted into heat
Is the change of direction the beam takes when passing through different structures
Directly removes energy from the beam
True or false? Beam divergence cannot occur after refraction of a curved surface
What is Rayleigh scattering?
When the interface the beam hits is
When the interface the beam hits is >1 wavelength, scattering occurs equally in two directions
When the interface the beam hits is >1 wavelength, scattering occurs equally in all directions
Why is scatter a disadvantage?
only a small portion of the beam returns to the transducer
It creates radiation dose to the patient
scattered waves interact with each other to form back scatter patterns
Mentally affects the operator
Which kind of reflection occurs when a soundwave strikes a large smooth surface?
non-specular
diffuse
specular
acoustic
What is acoustic impedance a product of?
the material's density and velocity of ultrasound in the material
the ultrasound's density and the velocity of the material
the weight of the transducer and the velocity of ultrasound in the material
the interface beam angle and the material density
True or False? Far gain is the amount of gain applied to the distant echoes
