Words to know before pathophysiology

Absorption

When sound waves lose energy as they travel through a material, turning into heat.

Acoustic impedance

How much resistance sound encounters when moving through a substance.

Aliasing

A type of distortion that happens when the ultrasound machine captures motion too fast to be displayed correctly.

Amplitude

The strength or loudness of a sound wave.

Angle of incidence

The angle at which a sound wave hits a surface.

Angle of reflection

The angle at which a sound wave bounces off a surface.

Attenuation

The weakening of a sound wave as it moves through a substance.

Axial resolution

How well an ultrasound can distinguish two objects that are close together along the direction of the sound beam.

Azimuthal resolution

How well an ultrasound can distinguish two objects that are side by side.

Color flow Doppler

A type of ultrasound that shows blood flow in different colors to indicate direction and speed.

Compression

The process of making the range of ultrasound signals easier to display and interpret.

Continuous wave Doppler (CW)

A type of Doppler ultrasound that continuously sends and receives sound waves to measure blood flow.

Cycle

One complete vibration of a sound wave.

Decibel (dB)

A unit that measures the strength of sound.

Depth gain compensation (DGC)

A setting that adjusts the brightness of deeper structures to make them clearer.

Doppler angle

The angle between the ultrasound beam and the direction of blood flow, which affects how accurately speed is measured.

Doppler shift

The change in frequency of a sound wave as it reflects off a moving object, used to measure blood flow.

Dynamic range

The range of signals the ultrasound machine can process, from the weakest to the strongest.

Focal zone

The area where the ultrasound beam is the sharpest and clearest.

Frame rate

How many images the ultrasound machine captures per second, affecting how smooth the image looks.

Frequency shift

A change in sound wave frequency due to movement, used in Doppler ultrasound.

Gain

A control that adjusts the brightness of the ultrasound image.

Gray scale

Different shades of gray in an ultrasound image that help distinguish different tissues.

Hertz (Hz)

A unit measuring the number of sound waves per second.

Gate

A control that selects a specific area to measure blood flow in Doppler ultrasound.

Intensity

The strength of the ultrasound beam.

Interface

The boundary between two different tissues where sound waves reflect.

Kilohertz (kHz)

A unit of frequency equal to 1,000 Hertz.

Laminar

Smooth, orderly blood flow in the same direction.

Lateral resolution

How well an ultrasound can distinguish two objects that are next to each other.

Megahertz (MHz)

A unit of frequency equal to 1 million Hertz, commonly used in ultrasound.

Nyquist sampling limit

The maximum speed that can be accurately measured with Doppler ultrasound before aliasing occurs.

Power

The strength of the ultrasound signal.

Pulse duration

The length of time an ultrasound pulse lasts.

Pulsed wave (PW) Doppler

A Doppler ultrasound that sends out pulses of sound instead of a continuous wave, allowing depth measurement.

Pulse repetition frequency (PRF)

How often ultrasound pulses are sent out per second.

Rarefaction

The part of a sound wave where the air or tissue is less dense.

Real time

The ability of ultrasound to display moving images instantly.

Reflection

When sound waves bounce off a surface and return to the ultrasound probe.

Refraction

When sound waves bend as they pass through different tissues.

Resistance

How much a material resists the movement of sound waves or blood flow.

Resolution

The ability to see small details in an ultrasound image.

Scattering

When sound waves hit small objects and spread out in different directions.

Slice thickness

The thickness of the ultrasound beam, which affects image clarity.

Spectral analysis

A detailed breakdown of Doppler signals to measure speed and direction of blood flow.

Spectral broadening

A widening of the range of Doppler signals, often due to turbulence or different speeds of blood flow.

Spatial pulse length

The physical length of one ultrasound pulse.

Temporal resolution

How well an ultrasound captures fast-moving objects over time.

Time gain compensation (TGC)

A control that makes deeper structures appear as bright as shallower ones.

Transducer

The part of the ultrasound machine that sends and receives sound waves.

Turbulent

Chaotic, irregular blood flow.

Velocity

The speed of movement, often referring to blood flow in ultrasound.

Wave

A repeated movement of sound energy.

Wavelength

The distance between two peaks of a sound wave.