Physics Final Penny Vocabulary Flashcards
the rule that states that it takes 13 microseconds for sound to travel 1 cm in soft tissue
13 us rule
the conversion of sound enery to heat
absorption
the production of bubbles in a liquid medium
acoustic cavitations
uses acoustic radiation force to compress the soft tissue and provides a qualitative measurement of stiffness without requiring pressure input from the sonographer
acoustic radiation force impulse imaging
the interference pattern caused by scatterers that produces the granular appearance of tissue on a sonographic image
acoustic speckle
changes that occur within a medium as a result of sound traveling through that medium
acoustic variables
as low as reasonably achieveable; the principle that states one should always use the lowest power and shortest scanning time possible to reduce potential exposure to the patient
ALARA
the wraparound of the spectral or Color Doppler display that occurs when the frequency shift exceeds the Nyquist limit; occurs only with pulsed-wave Doppler
aliasing
amplitude mode; the height of the spike on the image is related to the strength (amplitude) of the echo generated by the reflector
A-mode
the part of the receiver that increases or decreases the received echoes equally, regardless of depth
amplification
the maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector
amplitude
the part of the digital scan coverter that converts the analog signals from the receiver to binary for processing by the computer
analog-to-digital converter (A-to-D)
without echoes, or black
anechoic
the tool used to inform the machine what the flow angle is so that velocities can be accurately calculated
angle correction
the diameter of the piezoelectric element(s) producing the beam
aperture
the technique that varies the voltage to the individual elements to reduce grating lobes
apodization
the transducer with multiple active elements
array
echoes on the screen that are not representative of actual anatomy, or reflectors in the body that are displayed on the screen
artifacts
the rate at which sound is attenuated per unit depth
attenuation coefficient
a decrease in the amplitude and intensity of the sound beam as sound travels through tissue
attenation
the color Doppler processing technique that assesses pixels as stationary or in motion
autocorrelation
a portable device that is used to detect and treat abnormal heart rhytyms with electrical defibrillation
automatic external defribrillator
same as real-time ultrasound
automatic scanning
the ability to accurately identify reflectors that are arranged parellel to the ultrasound beam
axial resolution
the damping material of the transducer assembly, which reduces the number of cycles produced in a pulse
backing material
scattered sound waves that make their way back to the transducer and produce an image on the display
backscatter
the range of frequencies present within the beam
bandwidth
the acronym used to describe color Doppler scale: blue away, red towards
BART
the operator-adjustable dividing line between positive frequency shifts and negative frequency shifts on spectral and color Doppler
baseline
the part of the machine that shapes and steers the beam on the transmit end
beam former
the ratio of the center intensity to the average spatial intensity; also referred to as the SP/SA factor or beam uniformity coefficient
beam uniformity ratio
the principle that describes the inverse relationship between velocity and pressure
Bernoulli’s priniciple
a non-Doppler technology that offers real-time imaging of blood flow while scanning in gray scale
B-flow imaging
the Doppler device that can detect positive and negative Doppler shifts
bidirectional Doppler
the digital language of zeroes and ones
binary system
black and white image
bistable
the smallest unit of memory in a digital device
bit
brightness mode; the brightness of the dots is proportional to the strength of the echo generated by the reflector
B-mode
the stationary layer of blood vells immediately adjacent to the vessel wall
boundary layer
the term describing the intensity or luminance of the color Doppler display
brightness
eight bits of memory
byte
the muscles in the calf that, upon contraction, propel venous blood toward the heart
calf muscle pump
the ability of veins to store blood
capacitance
technology used to create comparable transducer technology to piezoelectric materials
capacitative micromachined ultrasound transducers
display that uses an electron gun to produce a stream of electrons toward a phosphor-coated screen
cathode ray tube (CRT)
acoustic noise in the color and/or spectral Doppler signal
clutter
a way of processing the pulse to improve contrast resolution and reduce speckle
coded excitation
accessory vessels that connect portions of the same blood vessel together
collateral blood vessels
Doppler shift information presented as a color (hue) superimposed over the grayscale image
color Doppler imaging
the setting for color Doppler that allows the operator to select frequency shift threshold; it determines whether color pixels should be displayed preferentially over grayscale pixels
color priority
a type of reverberation artifact caused by small reflectors (i.e. surgical clips)
comet tail
the function of the receiver that changes the brightness of the echo amplitudes to compensate for attenuation with depth
compensation
an area in the sound wave of high pressure and density
compression
the function of the receiver that decreases the range of signal amplitudes present within the machine’s receiver; opposite of dynamic range
compression (receiver function)
occurs when in-phase waves meet; the amplitudes of the two waves are added to form one large wave
constructive interference
the equation that describes the change in velocity as the area changes in order to maintain the volume of blood flow
continuity equation
sound that is continuously transmitted
continuous wave
Doppler device that uses continuous-wave ultrasound transmission; a device that consists of two elements, one element is used by the system to constantly transmit sound and the other is used to constantly receive sound
continuous wave Doppler
the ability to differentiate one shade of gray from another
contrast resolution
type of imaging in which an ultrasound contrast agent containing microscopic gas bubbles is used to improve visualization of structures or blood flow
contrast-enhanced ultrasound
the point at which a stenosis is hemodynamically significant with a pressure drop distal to the stenosis
critical stenosis
a synonym for the active element of the transducer, the piezoelectric part of the transducer assembly that produces sound
crystal
the temperature at which an ultrasound transducer will gain its piezoelectric properties, and also the temperature at which a transducer will lose the ability to produce sound if heated again above this temperature
Curie point
the transducer commonly referred to as a curvilinear or convex probe
curved sequenced arrayh
same as backing material; the part of the transducer assembly that reduces the number of cycles produced in a pulse
damping material
the process of reducing the number of cycles of each pulse in order to improve axial resolution
damping
a unit that establishes a relationship or comparison between two values of power, intensity, or amplitude
decibels
the function of the receiver that makes the signal easier to process by performing rectification and smoothing
demodulation
mass per unit volume
density
the inability to determine the depth of the reflector if the pulses are sent out too fast for them to be timed
depth ambiguity
occurs when out of phase waves meet; the amplitude of the resultant wave is smaller than either of the original waves
destructive interference
a group of metabolic diseases that result from a chronic disorder of carbohydrates metabolism
diabetes mellitus
a complication of diabetes that results from the severe lack of insulin
diabetic ketoacidosis
the relaxation of the heart following contraction
diastole
part of the digital scan converter that converts the binary signals from computer to memory to analog for display and storage
digital to analog converter (D-to-A)
relationship that implies that if one variable decreases, the other also decreases or if one variable increases, the other also increases;
directly related
how far apart objects are; may also be referred to as vibration or displacement
distance
spreading of the beam that occurs in the far zone
divergence
the change in the frequency of the received signal related to motion of reflector
Doppler effect
the equation that explains the relationship of the Doppler frequency shift and the propagation speed
Doppler equation
the test object used to evaluate the flow direction, the depth capability or penetration of the Doppler beam, and the accuracy of the sample volume location and measured velocity
Doppler phantom
real-time two-dimensional imaging combined with the spectral Doppler display
duplex
the percentage of time that sound is actually being produced
duty factor
the series of echo amplitudes present within the signal
dynamic range
refraction artifact caused by the curved surface of the reflector
edge shadowing
the sum of the individual resistances when multiple vessels are connected in series
effective resistance
a sonographic technique used to evaluate the stiffness of a mass or tissue
elastography
arc-like bands that occur when the machine is too close to an unshielded electrical device
electrical interference
the piezoelectric part of the transducer assembly that produces sound
element
the resoltion in the third dimension of the beam or the slick thickness plane
elevational plane
the resolution in the third dimension of the beam; the slice-thickness plane
elevational resolution
the difference in energy between two points
energy gradient
an artifact caused by sound passing through an area of lower attenuation
enhancement
the number of pulses per scan line in color Doppler; also referred to as packet size
ensemble length
the scientific study of creating tools and using equipment effectively in order to help the human body adjust to the work environment
ergonomics
pressure applied to the outside of an object
extrinsic pressure
the diverging part of the beam distal to the focal point
far zone
a mathematical process used for analyzing and processing the Doppler signal to produce the spectral waveform
fast Fourier transform
places grayscale pixels where there is no signal information based on adjacent scan lines; also referred to as pixel interpolation
fill-in interpolation
a motion artifact caused by the movement of tissue when using power Doppler
flash artifact
the volume of blood per unit time; typically measured in liter per minute or milliliter per second; represented by the symbol O
flow
the area of the beam with the smallest beam diameter
focal point
the portion of the transducer that is in contact with the patient’s skin
footprint
three-dimensional ultrasound in real-time
four dimensional ultrasound
the number of frames per second
frame rate
one complete ultrasound image
frame
far zone
Fraunhofer zone
averages the frequencies across the image to improve contrast resolution and reduce speckle
frequency compounding
the difference between the transmitted and received frequencies
frequency shift
near zone
Fresnel zone
a form of resistance, caused by two materials rubbing against each other, thereby converting energy to heat
friction
the operating or resonating frequency emitted by the transducer
fundamental frequency
technology that provides the ability to view alternate imaging modality during real-time sonographpy; also referred to as hybrid imaging
fusion imaging
an artifact caused by extraneous sound that is not located along primary beam path; occurs with arrays; reduced or eliminated apodization, subdicing, and tissue harmonics
grating lobes
the depth at which sound has lost half its intensity
half-intensity depth
harmonic signal produced by the patient’s tissue and that is a multiple of the fundamental frequency
harmonics
US law, which, among many goals, upholds patient confidentiality and requires the use of electronic medical records
Health insurance portability and accountability act
the study of blood flow through the vessels of the body
hemodynamics
inflammation of the liver
hepatitis
a unit of frequency
hertz
the ability to place echoes in the proper location horizontally and perpendicular to the sound beam
horizontal calibration
