Ultrasound terms cheat sheet
All the terms you should be familiar with to pass your ARDMS exam
Ultrasound terms dictionary
ULTRASOUND VOCABULARY
Analog-to-Digital (A-to-D) Converter
Digital-to-Analog (D-to-A) Converter
E
Edge Shadowing
Electrical Interference
Elevational Resolution
Energy Gradient
Ensemble Length
F
Far Zone
Fast Fourier Transform (FFT)
Fill-in Interpolation
Flash Artifact
Focal Zone
Frame Rate
Fraunhofer Zone
Fresnel Zone
Frequency Compounding
Frequency Shift
Fundamental Frequency
G
Grating Lobes
Gravitational Potential Energy
Grayscale Test Objects
H
Horizontal Calibration
Huygen’s Principle
I
In-Phase
Intensity Reflection Coefficient
Intensity Transmission Coefficient
Inversely Related
K
Kinetic Energy
L
Lab Accreditation
Laminar Flow
Lateral Resolution
Law of Conservation of Energy
Lead Zirconate Titanate
Linear Phased Array
Linear Sequenced Array
Liquid Crystal Display (LCD)
Longitudinal Waves
M
M-Mode
Master Synchronizer
Matching Layer
Mechanical Index
Mechanical Scanhead
Mirror Image
mm/Hg
N
Near Zone
Near Zone Length
Nonlinear Propagation
Non-directional Doppler
Non-sinusoidal
Non-specular Reflectors
Normal Incidence
Nyquist Limit
O
Oblique Incidence
Ohm’s Law
Out-of-Phase
Overall Gain
P
Packet Size
Particle Motion
Path Length
Persistence
Phase Quadrature
Phasic Flow
Piezoelectric Materials
Pixel (Picture Element)
Plug Flow
Poiseuille’s Law
Potential Energy
Power Doppler
Pressure Gradient
Preventative Maintenance
Propagation Speed
Pulse Duration
Pulse Repetition Frequency (PRF)
Pulse Repetition Period (PRP)
Pulsed Wave
Pulsed Wave (PW) Doppler
Q
Quality Assurance Program
Quality Factor (Q-Factor)
R
Range Ambiguity
Range Equation
Range Gate
Range Resolution
Rayleigh Scatters
Real-time
Read Zoom
Reynolds Number
Ring-down
S
Sample Volume
Scan Lines
Scan Converter
Shock Excitation
Side Lobes
Slice-Thickness Phantom
Slice-Thickness Plane
Snell’s Law
Spatial Pulse Length
Spatial Resolution
Speckle Reduction
Spectral Broadening
Specular Reflections
Sweep Speed
T
Tardus Parvus
Temporal Resolution
Tissue Doppler Imaging (TDI)
Tissue-Equivalent Phantom
Tissue Harmonics
Total Attenuation
Transmural Pressure
Transverse Waves
Turbulent Flow
V
Variance Mode
Vasa Vasorum
Velocity Mode
Vertical Depth
Viscous Energy
Voxel (Volume Element)
W
Wall Filter
Wave-front
Write Zoom
X
X-Axis
Y
Y-Axis
Z
Z-Axis
ULTRASOUND VOCABULARY
Amplitude mode; the height of the spike on the image is related to the strength
(amplitude) of the echo generated by the reflector.
The conversion of sound energy to heat.
The product of tissue density and ultrasound velocity.
The part of the receiver that increases or decreases the received echoes, equally,
ANALOG-TO-DIGITAL (A-TO-D) CONVERTER
The diameter of the piezoelectric element(s) producing the beam.
The technique that varies voltage to the individual elements to reduce grating lobes.
The transducer with multiple active elements.
The rate at which sound is attenuated per unit depth. Frequency/2
The color Doppler processing technique that assesses pixels as stationary or in motion.
Longitudinal, Axial, Range, Radial, & Depth) (1/2 SPL) B-MODE
The range of frequencies present within the beam.
Acronym used in echocardiography describing color Doppler scale: “Blue Away, Red Toward”.
The instrument that shapes and steers the beam on the transmit end.
The principle that describes the inverse relationship between velocity and pressure.
The digital language of zeroes and ones.
The Doppler device that can detect positive and negative Doppler Shift.
The smallest unit of memory in a digital device.
The extension of color beyond the region of flow to the adjacent tissue.
The stationary layer of blood cells immediately adjacent to the vessel wall.
The muscles in the calf that, upon contraction, propel venous blood toward the heart.
Display that uses an electron gun to produce a stream of electrons toward a phosphor-coated screen.
The interaction of the sound waves with microscopic gas bubbles in the tissue.
A way of processing the pulse to improve contrast resolution and reduce speckle.
Doppler shift information presented as a color (hue) superimposed over the grayscale image.
AKA Ring Down is a type of reverberation artifact caused by small reflectors (i.e.,
surgical clips, or metal objects).
Occurs when in-phase waves meet; the amplitudes of the two waves are added to form one large wave.
Doppler device that uses continuous wave ultrasound transmission.
Sound that is continuously transmitted.
The ability to differentiate one shade of gray from another.
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. (300-400 C)
The transducer commonly referred to as curvilinear or convex probe.
The area closest to the transducer is evaluated by using on the top surface of the
object and scanning the pins located at the top of the test subject.
A unity that establishes a relationship or comparison between two values of power or intensity.
Mass per unit volume. Measured per centimeter cubed (kg/cm3).
The relaxation of the heart following contraction.
Spreading of the beams that occurs after the focal zone.
DIGITAL-TO-ANALOG (D-TO-A) CONVERTER
Combination of color Doppler and power Doppler that provides the sensitivity of
power Doppler with color Doppler’s ability to provide for direction of blood flow.
How far apart objects are. Measured in feet, inches, centimeters or miles.
Spreading of the beam that occurs in the far zone.
The change in the frequency of the received signal related to motion of reflector.
The real-time 2D imaging combined with the spectral Doppler display.
The percentage of time that sound is actually being produced.
The series of echo amplitudes present within the signal.
Refraction artifact caused by the curved surface of the reflector.
Arc-like bands that occur when the machine is too close to an unshielded electrical device.
The piezoelectric part of the transducer assembly that produces sound.
The difference in energy between two points (E1 vs E2).
An artifact caused by sound passing through an area of lower attenuation.
The number of pulses per scan line in color Doppler; also referred to as “packet size”.
Changing the radio frequency signal into a video signal.
The diverging part of the beam distal to the focal point. Also known as “Fraunhofer Zone”.
One half of a frame on the display. (1/2 frame) FILL-IN INTERPOLATION
Places pixels where there is no signal information based on adjacent scan lines.
A motion artifact caused by the movement of tissue when using power Doppler.
The volume of blood per unit time; typically measured in L/min or mL/s; by the symbol Q.
The location where the diameter of the beam is its smallest.
The portion of the transducer that is in contact with the patient’s skin.
One complete ultrasound image.
The number of frames per second.
The number of cycles per second. Measured in Hertz (Hz), kilohertz (kHz), or megahertz (MHz).
Averages the frequencies across the image to improve contrast resolution and reduce speckle.
The difference between the transmitted and received frequencies.
A form of resistance; caused by two materials rubbing against each other, thereby
The operating or resonating frequency emitted by the transducer.
GRAVITATIONAL POTENTIAL ENERGY
The study of blood flow through the blood vessels of the body.
The ability to place echoes in the proper location horizontally and perpendicular to the sound beam.
A term used to describe displayed colors (e.g., red, blue, green).
Displayed echoes that are relatively darker than the surrounding tissue.
A device used to measure output intensity of the transducer.
The resistance to the propagation of sound through a medium.
Waves whose peaks and troughs overlap.
The power of the wave divided by the area over which it is spread; the energy per
INTENSITY REFLECTION COEFFICIENT
The percentage of sound reflected at an interface.
INTENSITY TRANSMISSION COEFFICIENT
The percentage of sound transmitted at an interface.
The dividing line between two different media.
The energy form of flowing blood.
The total amount of energy in a system never changes, although it might be in adifferent form from which it started.
Abbreviated as PZT, this is the man-made ceramic of which many transducer elements are made.
The transducer that used phasing, or small time differences, to steer and focus the beam.
The transducer commonly referred to as a “linear probe”.
Display that uses the twisting and untwisting of liquid crystals in front of a light source.
The molecules of the medium vibrate back and forth in the same direction that the wave is traveling.
The brightness of the color Doppler image.
Motion mode; used to display motion of the reflectors.
The parameter that describes the acoustic output in terms of the likelihood of cavitation.
Transducers with a motor for steering the beam.
Any form of matter: solid, liquid, or gas.
The part of the beam between the element and the focal point. Also known as “Fresnel Zone”.
The length of the region from the transducer face to the focal point.
Doppler device that cannot differentiate between positive and negative frequency shifts.
Waves that are not pure sine waves.
Reflectors that are smaller than the wavelength of the incident beam. (Red Blood Cells)
Low-level echoes on the display that do not contribute useful diagnostic information.
Angle of incidence is 90° to the interface. NYQUIST LIMIT
The maximum frequency shift sampled without aliasing; equal to one half the pulse
repetition frequency (PRF). (1/2 PRF)
Angle of incidence is lesser than or greater than 90° to the interface.
A law used in electronics in which flow is equal to the pressure differential divided by resistance.
The component of a continuous wave Doppler device that produces the voltage
Receiver function that increases or decreases all the echo amplitudes equally.
The number of pulses per scan line; also called ensemble length.
The movement of molecules due to propagating sound energy.
The time it takes for one cycle to occur. (Determined by transducer)
The averaging of color frames in order to display blood flow with a low signal-to- noise ratio.
The ability to convert pressure into electricity and electricity into pressure.
The smallest component of a 2D digital image.
The flow profile represented by blood typically at the same velocity.
The law that describes the relationship of resistance, pressure, and flow.
Pressure energy created by the beating heart.
Occurs in the D-to-A converter; the image must be frozen.
The rate at which work is performed or energy is transmitted.
Occurs in the A-to-D converter; the image must be live.
The difference between pressures at two ends of a blood vessel.
PULSE REPETITION FREQUENCY (PRF)
The time taken for a pulse to occur. Measured in milliseconds (ms).
Sound that is sent out in pulses.
A measure of beam purity; the operating frequency of the transducer divided by the bandwidth.
The ability to determine the depth of echoes by timing how long it takes for the echoes to travel from the transducer to the reflector and back. Utilized by pulsed- wave devices.
An area in the sound wave where the molecules are spread wider apart.
Reflectors smaller than the wave length (RBC’s).
Live ultrasound, also known as “automatic scanning”.
The component of the machine that processes the signals coming returning from the patient.
The echo; part of sound that returns from an interface.
The part of the receiver that inverts the negative voltages to positives.
A change in direction or bending of the sound wave as it passes through one tissue into another. The part of the beam that is bent is the transmitted beam. (Causes Shadowing)
The ability to place echoes in the correct location.
A type of reverberation artifact caused by air.
The area within the range gate where the Doppler signals are obtained.
The amount of white added to a hue; the whiter there is, the less saturated the color.
Number of lines per frame. AKA Line Density.
Ability of a test to detect disease.
Applying electrical energy to the piezoelectric element causes it to resonate.
The third dimension of the beam. Also known as “Elevational Plane” and “Section- Thickness Plane”.
A traveling variation in pressure.
The length of a pulse. Measured in millimeters (mm). (Determines Axial Resolution image quality)
Refers to Axial, Lateral, Contrast, and Elevational Resolution.
Ability to detect the absence of a disease.
Algorithm used in signal processing to reduce the amount of acoustic speckle.
The filling of the spectral window.
Pathologic narrowing of a blood vessel.
The ability of an object to resist compression and relates to the hardness of a medium.
Dividing the piezoelectric elements into very small pieces to reduce grating lobes.
The time period of the cardiac cycle when the heart is contracting.
Color Doppler Imaging technique used to imagine wall motion.
The total amount of sound (in dB) that has been attenuated at a given depth.
The pressure inside a vessel compared with the pressure outside of a vessel.
Type of wave in which the molecules in a medium vibrate at 90° to the direction of travel.
The ability to visualize real-time grayscale, color Doppler, and spectral Doppler simultaneously.
Component of the backing material.
Chaotic, disorderly flow of blood.
A network of small blood vessels that supply blood to the walls of arteries and veins.
The color Doppler scale with mean velocities displayed vertically.
The distance from the transducer.
The energy loss caused by friction.
The smallest component of a 3D image.
The length of a single cycle of sound.
A small wave created as a result of Huygen’s Principle.
The plane that is perpendicular to the beam path. (Lateral Resolution)
The plane that is parallel to the beam. (Axial Resolution)
The brightness, or amplitude, of the dots on the display.