Ultrasound Physics Relationships

Related

- two items that are associated or affiliated

Unrelated

- two items that are NOT associated, or lacking a logical or casual connection

Directly Related or Directly Proportional

- when one item INCREASES, the other INCREASES

Inversely Related or Inversely Proportional

- when one item INCREASES, the other DECREASES

Reciprocal Relationship

- when two numbers with a reciprocal relationship are multiplied together, the result is 1

- special form of inverse relationship

- reciprocals are inversely related because when one increases, the other decreases

Period (T) and Frequency (f)

- inversely related

- f(o) = 1/T

- as frequency increases, period decreases

- as frequency decreases, period increases

- reciprocals

- the product of (frequency) and (period) is always 1

- f(o) x T = 1

Power (P) and Amplitude (p)

- directly related

- power is proportional to the wave's amplitude squared

- power ∝ amplitude^2

Intensity (I) and Power (P)

- directly proportional

- when a wave's power is doubled, the intensity is doubled

- when a wave's power is quartered, the intensity is quartered

- intensity ∝ power

Intensity (I) and Amplitude (p)

- directly proportional

- intensity is proportional to the wave's amplitude squared

- when a wave's amplitude is doubled. the intensity increases to four times its original value

- intensity ∝ amplitude^2

Wavelength (λ) and Frequency (f)

- inversely related

- as long as a wave remains in one medium, wavelength and frequency are inversely related

- as frequency increases, wavelength decreases

- the lower the frequency, the longer the wavelength

- f(o) = c/λ

Stiffness and Speed (c)

- directly related

- when stiffness increases, speed increases

Density (ρ) and Speed (c)

- inversely related

- when density increases, speed decreases

- materials that are stiff but not dense will have the fastest speed

- materials that are not stiff but are very dense will have the slowest speed

Spatial Pulse Length (SPL) and Frequency (f)

- inversely related

- because wavelength decreases with increasing frequency, spatial pulse length decreases with increasing frequency

Spatial Pulse Length (SPL) and the number of cycles per pulse

- directly proportional

- spatial pulse length equals the number of cycles in each pulse times the wavelength of each cycle

Spatial Pulse Length (SPL) and Wavelength (λ)

- directly related

- spatial pulse length is the product of the number of cycles in a pulse and the wavelength

Spatial Pulse Length (SPL) and Pulse Duration (PD)

- directly related

- if spatial pulse length increases, pulse duration increases

- if spatial pulse length decreases, pulse duration decreases

Spatial Pulse Length (SPL) and Speed

- directly related

Pulse Duration (PD) and the number of cycles

- directly related

- if the number of cycles increases, pulse duration increases

- if the number of cycles decreases, pulse duration decreases

Pulse Duration (PD) and Period (T)

- directly proportional

Pulse Duration (PD) and Frequency (f)

- inversely proportional

Pulse Repetition Period (PRP) and Depth of View

- directly related

- as depth of view increases, pulse repetition period increases

- as depth of view decreases, pulse repetition period decreases

Pulse Repetition Frequency (PRF) and Depth of View

- inversely related

- as depth of view increases, pulse repetition frequency decreases

- as depth of view decreases, pulse repetition frequency increases

Pulse Repetition Frequency (PRF) and Frequency

- unrelated

- PRF is only related to depth of view

Pulse Repetition Period (PRP) and Pulse Repetition Frequency (PRF)

- inversely related

- a longer pulse repetition period results in a lower pulse repetition frequency (PRP = 1/PRF)

- a shorter pulse repetition period results in a higher pulse repetition frequency (PRF = 1/PRP)

- reciprocals

- when two parameters are multiplied together, the result is 1

- PRF x PRP = 1

Distance (d) and Attenuation

- directly related

- the distance that the sound travels directly affects attenuation

- the farther sound travels, the greater the attenuation and the weaker the beam becomes

Frequency (f) and Attenuation

- directly related

- attenuation in a soft tissue depends upon the wave's frequency

- attenuation is greater in higher frequency sound that in lower frequency sound

Attenuation and Scattering

- directly related

- attenuation is the loss of intensity with distance traveled, caused by scattering and absorption of the beam

Attenuation and Absorption

- directly related

- the higher the frequency of the sound wave, the greater amount fo absorption will occur

Attenuation and Reflection

- directly related

Frequency and Absorption

- directly related

- absorption is dependent on the frequency of the sound wave and the characteristics of attenuating tissue

Frequency and Scattering

- directly related

- scattering has a strong dependence on increasing ultrasound frequency

- higher frequency beams scatter much more than lower frequency beams

Frequency (f) and Depth of Penetration

- inversely related

- as frequency decreases, depth of penetration increases

- the higher the frequency, the shorter the distance the field can penetrated into the body

Frequency and Resolution

- directly related

- ultrasound waves with shorter wavelengths have higher frequency and produce higher resolution images

Time of Flight and Depth

- directly related

- greater distances prolong the time of flight

- lesser distances shorten the time of flight

When the Depth of View is shallow, Pulse Repetition Period (PRP) is _______.

- short

When the Depth of View is deep, Pulse Repetition Period (PRP) is _______.

- long

When Depth of View is shallow, Pulse Repetition Frequency (PRF) is _______.

- high

When Depth of View is deep, Pulse Repetition Frequency (PRF) is _______.

- low

Pulse Duration (PD) and Bandwidth

- inversely related

- the larger the bandwidth of the receiver, the shorter the rise time of the edges of the pulse duration

Quality Factor and Bandwidth

- inversely related

- q-factor is a unitless number

- wide bandwidth probes have a low q-factor

- narrow bandwidth probes have a high q-factor

Speed of Sound in PZT and Frequency of Sound

- directly related

- when the speed of sound in PZT is faster, the frequency of sound created by a pulsed wave transducer is higher

- when sound's speed in PZT is slower, the frequency is lower

PZT Thickness and Frequency

- inversely related

- thicker active elements create pulses with lower frequency, longer wavelength cycles

- thinner active elements create pulses with higher frequency, shorter wavelength cycles

Transducer Diameter and Focal Depth

- directly related

- a larger diameter results in a deeper focus

Frequency and Focal Depth

- directly related

- high frequency sound results in a deeper focus

Frequency and Near Zone Length

- directly related

- the higher the frequency, the shorter the length of the near zone

Wavelength and Near Zone Length

- inversely related

PZT Active Element Diameter and Near Zone Length

- directly related

Crystal Diameter and Beam Divergence

- inversely related

- smaller diameter crystals produce beams that spread out more in the far field

- larger diameter crystals produce beams that diverge less in the far field

Frequency and Beam Divergence

- inversely related

- lower frequency sound beams spread out or diverge more in the deep far zone

- higher frequency sound beams diverge less

Frame Rate and Time for One Frame

- inversely related

- as the time needed to make such image decreases, the frame rate increases

- reciprocal

- when the frame rate is multiplied by time for one frame, the result is 1

- T(frame) x Frame Rate = 1

Imaging Depth and Frame Rate

- inversely related

- shallow imaging increases frame rate and improves temporal resolution

- deeper imaging decreases frame rate and degrades temporal resolution

Imaging Depth and Pulse Repetition Period (PRP)

- directly related

- if depth increases, pulse repetition period increases

- if depth decreases, pulse repetition period decreases

Imaging Depth and Pulse Repetition Frequency (PRF)

- inversely related

- if depth increases, pulse repetition frequency decreases

- if depth decreases, pulse repetition increases

Imaging Depth and Power

- inversely related

- if depth increases, power decreases

- if depth decreases, power increases

Intensity and Imaging Depth

- inversely related

- if depth increases, intensity decreases

- if depth decreases, intensity increases

Duty Factor (DF) and Pulse Repetition Period (PRP)

- inversely related

- if duty factor % increases, pulse repetition period decreases

- if duty factor % decreases, pulse repetition period increases

Duty Factor (DF) and Imaging Depth

- inversely related

- f depth increases, duty factor % decreases

- if depth decreases, duty factor % increases

Pulses per Frame and Frame Rate

- inversely related

- higher frame rates are possible when each individual image is made with fewer pulses

- lower frame rates occur when each image is made with more pulses

Field of View (Sector Size) and Frame Rate

- inversely related

- when a sonographer expands the field of view (sector size), more pulses are required to create an image

- narrower (upper) images result in higher frame rates

- wider (lower) images result in lower frame rates

Line Density and Frame Rate

- inversely related

- when line density is low, few pulses create each image and the frame rate is high

- when line density is high, the number of pulses per image increases, frame rate drops

Doppler Shift and Velocity

- directly related

- the faster the velocity, the greater the doppler frequency

Doppler Shift and Frequency

- directly related

- if the transducer's frequency is doubled, the measure doppler shift will also be doubled

Impedance (Z) , Density (ρ), and Propagation Speed (c)

- directly proportional