Soundwave Characteristics

To write with sound

(Sonography)

The word "sonography" means...?

-Ultrasound waves
-Echos

(What Does The Ultrasound Transducer Do?)

The ultrasound transducer emits ____________ that are sent into tissues and then reflect off of them, creating _________ that travel back to the transducer

Ultrasound pulse

The transducer emits an ______________

Reflection

(The Ultrasound Pulse)

The ultrasound pulse travels into the tissue and reflects off of structures and then comes back to the transducer. We use this __________ to create an image

128

(Creating a Sector Image)

How many pulses/lines in a typical sector?

Brightness

(The B-Mode Image)

What does the "B" in B-mode image stand for?

A signal received from the echo coming back

(The B-Mode Image)

The machine is going to assign a brightness to each white dot. What do the white dots represent?

-Strength
-Returning pulse

(The B-Mode Image)

A white dot means that there is a structure in that spot. The brightness of the structure on the screen is determined by the ____________ of the ____________

-Stronger
-Weaker

(The B-Mode Image)

Brighter dots represent __________ returning echo's, whereas darker dots represent _________ returning echo's

70

(Real Time 2D Echocardiography)

Real time 2D echocardiography creates _________ frames per second

1

(Real Time 2D Echocardiography)

How many frames is a sector, a.k.a. a still image?

Chambers

(Real Time 2D Echocardiography)

Areas with less white dots/the darker/black areas are the __________ of the heart

Walls

(Real Time 2D Echocardiography)

Areas with more white dots/brighter/white areas are the __________ of the heart

Brighter/white

(Real Time 2D Echocardiography)

The ____________ areas reflected the ultrasound pulse back to the transducer

Pericardium

(Real Time 2D Echocardiography)

The super bright, thick part at the bottom of the sector is the _____________

-Pericardium
-Because it reflects the ultrasound pulse the most

(Real Time 2D Echocardiography)

The ___________ is the brightest part of the whole heart. Why?

Top

(Real Time 2D Echocardiography)

The transducer is always at the __________ of the sector/triangle

Acoustic variables

(Elementary Principles of Ultrasound: Sound Waves)

A sound wave is a propagating variation in ______________

Traveling

(Elementary Principles of Ultrasound: Sound Waves)

A sound wave is a __________ change in acoustic variables

-Particle motion
-Density
-Pressure (acoustic pressure)

(Elementary Principles of Ultrasound: Sound Waves)

What are the 3 acoustic variable?

Sound wave passes

(Elementary Principles of Ultrasound: Sound Waves)

The acoustic variables change as the...?

-Energy
-It is being transferred

(Acoustic Variables)

The variable that is actually changing as the sound wave passes is the _____________. How?

True (particles are NOT being transferred)

(Acoustic Variables)

True or False:

As the sound wave passes, the actual physical particles are NOT moving; There is NO net movement of particles

Compression

(Acoustic Variables)

____________ is when the particles get squished together

-It causes particle motion
-The density is increased
-Acoustic pressure is increased

(Acoustic Variables)

How does compression of the particles cause changes in the acoustic variables?

Increases

(Acoustic Variables)

When we compress the particles, the density __________

Increased

(Acoustic Variables)

Acoustic pressure is _____________ in areas of compression, in which the particles were squished together

Decreased

(Acoustic Variables)

Acoustic pressure was ____________ in areas of rarefaction, in which the particles were spread apart

Up

(Acoustic Variables)

The wave goes ________ during compression

Longitudinal

A _______________ wave travels parallel to particle motion

Same

(Longitudinal Wave)

In a longitudinal wave, the direction of particle motion is in the __________ direction in which the wave is traveling

-Horizontal
-Horizontally

(Longitudinal Wave)

In a longitudinal wave, the particle motion is ____________ and the wave travels ____________

0

(Longitudinal Wave)

What is the net movement of particle motion in a longitudinal wave?

Longitudinal

Each ultrasound pulse is a ____________ wave

Transverse

A ________________ wave travels perpendicular to particle motion

-Vertical
-Horizontally

(Transverse Wave)

In a transverse wave, particle motion is ________ and the wave travels ____________

In-phase

(In-Phase and Out-of-Phase Waves)

_____________ waves are waves that have different strengths but have the same timing

Out-of-Phase

(In-Phase and Out-of-Phase Waves)

______________ waves are waves that have different timing

Interference

(In-Phase and Out-of-Phase Waves)

Waves are going to combine as they travel. As a result, this creates _______________

-Constructive
-Increases it

(Interference)

If waves are in-phase and they combine, the result is _______________ interference. What does this do to the size of the waves?

-Destructive
-Decreases

(Interference)

If waves are out-of-phase and they combine, the result is _________________ interference. What does this do to the size of the waves?

-Mechanical waves
-Electromagnetic waves

(Two General Types of Waves)

What are the 2 general types of waves?

Matter/particles

(Two General Types of Waves)

What do mechanical waves need?

-Ocean waves
-Seismic waves
-Sound waves

(Two General Types of Waves)

What are the 3 categories of mechanical waves?

Mechanical

(Two General Types of Waves)

Sound is a ____________ longitudinal wave

-Radio waves
-X-rays
-Light

(Two General Types of Waves)

What are the 3 categories of electromagnetic waves?

-Frequency
-Period
-Amplitude
-Wavelength
-Propagation speed

(Characteristics of Sound)

What are the 5 characteristics of sound?

The number of sound cycles per second

(Frequency)

What is frequency?

Hertz (Hz)

(Frequency)

What are the units of frequency?

Sound source (the machine)

(Frequency)

Frequency is determined by the ___________

When acoustic pressure starts to go up from baseline, goes up, and the goes back down to baseline

(Frequency)

When does a sound cycle begin?

When the wave comes back up to the baseline

(Frequency)

When does a sound cycle end?

Compression

(Frequency)

____________ is when acoustic pressure, starting from baseline, goes up and then goes back down to baseline

Rarefaction

(Frequency)

_____________ is when acoustic pressure, starting from baseline, goes down and then comes back up to baseline

1,000

(Frequency)

There are _________ Hz in 1 kilohertz (kHz)

1,000,000 (1 million)

(Frequency)

There are _____________ Hz in 1 megahertz (MHz)

1,000

(Frequency)

There are ____________ milliseconds in 1 second

1,000,000 (1 million)

(Frequency)

There are ___________ microseconds in 1 second

5

(Frequency)

5 cycles/sec=________ Hz

5,000

(Frequency)

5 cycles/millisecond=_________ Hz

5

(Frequency)

5,000 Hz=_______ kHz

5,000,000 (5 million)

(Frequency)

5 cycles/microsecond=_______ Hz

5

(Frequency)


5,000,000 Hz=__________MHz

-Greater
-20,000 Hz (20 kHz)

(Frequency)

Ultrasound is sound with a frequency ___________ than ____________

-Less
-20 Hz

(Frequency)

Infrasound (used by sonar) is sound with a frequency _________ than _________

20-20,000 Hz (20 Hz-20 kHz)

(Frequency)

What is the frequency range of human hearing?

2-12 MHz (2 million-12 million Hz)

(Frequency)

What is the range of diagnostic imaging frequencies?

The duration of 1 cycle

(Period)

What is period?

Period=1/frequency

(Period)

What is the equation for period?

Sound source

(Period)

Period is determined by the ___________

Decreased

(Period)

Increased frequency=__________ period

Higher

(Period)

___________ frequency=More cycles per second=Shorter period

Increased

(Period)

Decreased frequency=____________ period

Lower

(Period)

__________ frequency=Less cycles per second=Longer period

The loudness of sound

(Amplitude)

Amplitude is the measure of...?

Amplitude

The maximum variation in an acoustic variable is the ______________

Sound source

(Amplitude)

Amplitude is initially determined by the _____________

Transducer

(Amplitude)

The machine, through the _________, determines the amplitude

Decreases (gets weaker)

(Amplitude)

As sound travels through the body, the amplitude _____________

The length of 1 cycle

(Wavelength)

What is wavelength?

Distance

(Wavelength)

Wavelength is associated with _____________

-Period is associated with time
-Wavelength is associated with distance

What is the difference between period and wavelength?

Wavelength=Propagation speed/Frequency

(Wavelength)

What is the equation for wavelength?

-Sound source
-Medium
-Because wavelength depends on the frequency, which is determined by the sound source, and the propagation speed, which is determined by the medium

(Wavelength)

Wavelength is determined by the __________ and the ___________. Explain.

Propagation speed

(Wavelength)

__________________ is how fast the sound is traveling through the medium

It spreads it out

(Wavelength)

If sound travels faster, what does it do to the wavelength?

Shorter

(Wavelength)

Higher frequency=_________ wavelength

The rate at which sound travels in a medium

(Propagation Speed)

What is propagation speed?

Proportional

(Propagation Speed)

The propagation speed is ___________ to the stiffness of the medium

Inversely proportional

(Propagation Speed)

The propagation speed is ____________ to the density of the medium

Soft tissue

(Propagation Speed)

The medium is typically called ____________

Air

(Propagation Speed)

Sound travels the slowest through which medium?

Bone

(Propagation Speed)

Sound travels the fastest through which medium?

m/sec

(Propagation Speed)

What are the units used for propagation speed

1540 m/sec

(Propagation Speed)

What is the propagation speed through soft tissue?

-Stiffness
-Density

(Propagation Speed)

Propagation speed is related to the ___________ and ___________ of the medium

Stiffness of the medium

(Propagation Speed)

Which has the greater effect on propagation speed: Stiffness of the medium or density of the medium?

Increased (wave travels faster)

(Propagation Speed)

Greater stiffness of the medium=______________ propagation speed

It also increases

(Propagation Speed)

As the stiffness of the medium increases, what happens to the density of the medium?

The distance from the transducer to the reflector

(Positioning of Structures)

What is the range equation used to calculate?