10/30 Quiz Flashcards by Nya Sanchez-Fernandez

Name the 3 equations for NZL

(Diameter x Frequency) / 6.16
Radius Squared / wavelength
(Diameter squared x Frequency) / 6

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What is the equation for speed of sound

c = f x wavelength

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What is the equation for wavelength

Wavelength = c/f

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What 2 transducer factors affect NZL

Diameter/Apeture of transducer
Frequency of sound produced by transducer

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What 2 things create a beam with a deeper foci

Large crystal, high frequency sound

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Smaller diameter crystals produce beams that

Diverge more into the far zone

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Which of the folling probes create beams with shallow focus
A) Small dia, high f
B) Small dia, low f
C) Large dia, high f
D) Large dia, low f

B) Small dia, low f

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Which of the following probes creates beams with deepest focus
A) 4 mm dia, 4 MHz
B) 5 mm dia, 8 MHz
C) 6 mm dia, 2 MHz
D) 6 mm dia, 8 MHz

D) 6 mm dia, 8 MHz

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The lower the frequency of the beam used, the greated the

Expansion of the beam into the far field region

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What is the far field divergence angle

Angle between beam axis and the boundary of the beam in the far field

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What is the 2 equations for far field divergence angle

Sin0 = (1.2 x wavlength) / Dia
Sin0 = (1.2 x Prop speed) / (Dia x f)

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If you have a large diameter you will have a ___ angle

Smaller angle

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Which of the following probes create a beam with most divergence
A) Small dia, high f
B) Small dia, low f
C) Large dia, high f
D) Large dia, low f

B) Small dia, low f

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What is the range of the sine of an angle

0-1

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As the sine of an angle increases what will happen to the actual angle

Increase

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What are the 3 forms of flows

Pulsatile
Phasic
Steady

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Definition of pulsatile flow

Variable velocity flow due to cardiac contraction

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What is an example of pulsatile flow

Arterial circulation

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Definition of phasic

Variable velocity due to respiration

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What is an example of phasic flow

Venous circulation

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Definition of steady flow

Contrast velocity flow

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What is an example of steady flow

When holding one’s breathe

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What is laminar flow

Layered flow-liquid at different speeds as we move from vessel wall

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As part of a boundary condition flow must = 0 at

Vessel wall

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What are the 2 types of laminar flow

Parabolic Plug flow

Define parabolic flow

Avg. flow speed = 1/2 max slow speed at center

Define plug flow

All layers flow at same speed

What is disturbent/turbulent flow

Randome or chaotic circles or eddies

What are the typical regions for disturbing/turbulent

Stenoses

What is stenosis

Narrowing of a vessel or at bifurcation a vessel that splits into 2 regions

What is blood flow is stenosis

Blood flow is changed and can be described by Bernoulli's equation

What is Bernoulli's equation for stenosis

P + 1/2pv^2 + pgh = Constant

What is the P stand for in Bernoulli's equation What is the equation for this What are the units

Pressure P = F/a Pascals

What does the p stand for in Bernoulli's equation What are the units

Density kg/m^3

What does the pv^2 for in Bernoulli's equation

Kinetic Energy

What does the pgh stand for in Bernoulli's equation

Potential energy

In the 1st equation if the P is high and kinetic energy is low then what should the P and kinetic energy be in the second equation

P should be low and kinetic energy should be high

P(1) + pv^2(1) + pgh =

P(2) +pv^2(2) +pgh

What is continuity flow

Volume flow rate must be constant in the before, at and after constriction regions

What does continuity of flow mean

Blood is not created or destroyed as it moves through the vessel

Equation of pressure gradient

PG = Flow x Resistance

T or F: A) PI has units B) RI has not units

A) F - PI has no units B) T

What does PI stand for What is the equation

Pulsatility index PI = (Max-Min) / Ave

Pulsatility index is where the max and min are the peak _____ and minimum ____ velocities and average _____

Peak systolic, minimum diastolic, average flow

Max velocity is 60 cm/s, Min velocity is 20 cm/s, Average flow is 40 cm/s What is the PI?

(60 cm/s - 20 cm/s) / 40 cm/s = 1

What does RI stand for What is the equation

Resistivity index RI = (Max-Min) / Max

RI is a useful parameter in diagnosis of

Arterial seconds

Max velocity is 60 cm/s, Min is 20 cm/s What is the RI

(60 cm/s - 20 cm/s) / 60 cm/s 2/3 or 0.666666666

Technique used to quantify and image blood flow, turn would mean we're checking heart motion

Doppler

What is the basic premise of Doppler

Relative motion between sound source and observer

What are the 3 ways to produce Doppler

1. Source moves and listener is stationary 2. Listener is moving but the source is stationary 3. Source moves and listener moves

What is the equation for Doppler shift

Doppler shift (Hz) = Reflected frequency - Transmitted frequency

Doppler effect is a smaller ____ riding along with transducers main ______. And we decouple them by

Smaller signal, transducers main frequency, decouple them by demodulation

Reflected frequency is 2.02 MHz, transmitted frequency is 2.00 MHz. What is the Doppler shift

2.02 (MHz) - 2.00 (MHz) = -0.02 MHz

In a positive Doppler shift what will happen to the following: Frequency - Increases or Decreases Wavelength - Increases or Decreases

f - Increase Wavelength - Decrease

In a negative Doppler shift what will happen to the following: Frequency - Increases or Decreases Wavelength - Increases or Decreases

f - Decrease Wavelength - Increase

What is the other equation for Doppler

f(D) = 2f(o)vcos0 / c

fo in Doppler equation stands for

Original frequency

What does the v in the Doppler equation stand for

Speed of RBC's

What does cos0 stand for in the Doppler equation

Cosine of angle

What does the c stand for in the Doppler equation

Speed of sound

If the original frequency is high then the Doppler freqeuncy will be (High or Low)

High

If the cosine angle is 0 degress it will = It is the (Max or Min) And the view is right at the ______ What color does this show on U/S

Will = 1 Max Transducer Red

If the cosine angle is 90 degress it will = It is the (Max or Min) The view is ____ to flow In this degree you can't see

0 Min View is perpendicular to flow Direction of flow

If the cosine angle is 180 degrees it will = It is the (Max or Min) What color does this show on U/S

-1 Max Blue

If the cosine angle is 60 degress it will =

1/2

You should always assume the cosine angle is

60 degrees