vasc 2 midterm

Change in frequency of sounds, light, or other waves caused by the motion of the source or the observer

What is the Doppler effect

Change in frequency of sound caused by the motion of rbc's

What is doppler in ultrasound

Difference between transmitted frequency and received frequency

What is the doppler shift

Receiver frequency - transmitted frequency

How do you calculate the doppler shift

Doppler shift equation, not the complicated one

How do the machine detect/calculate doppler shift

Rbc's moving toward transducer, antegrade flow

What is a positive doppler shift

Cells moving away from the transducer, retrograde flow

What is a negative doppler shift

Larger

If the cells are moving toward the transducer will the echo frequency be larger or smaller

Smaller

If the cell are moving away from the transducer will the echo frequency be large or smaller

Blood velocity and cosine of the doppler angle

What are the two most important factors that affect the doppler shift

F= (2Fo x v x Cos0) / C

What is the doppler equation

Hertz or kilohertz

What unit is the doppler shift usually in

True

T/F: the doppler shift is usually in the audible range

We can hear spectral doppler

What does it mean that the doppler shift is usually in the audible range

Blood velocity

What is the doppler shift directly proportional to

Higher shifts

Faster blood =

Angle

What is the doppler shift inversely related to

Higher shifts

Smaller angles =

Lower shifts

Larger angles =

No shift

Perpendicular (90 degrees) =

False

T/F: when there is no doppler shift it always means that there is no flow

No flow, poor doppler angle, poor setup

What can the absence of Doppler shift be caused by

Average doppler shifts

What does colour doppler detect within the colour box

Lower doppler shifts

What does darker colours mean on the colour map

Higher doppler shifts

What does lighter colours mean on the colour map

True

T/F: for any vascular study, the baseline is typically centred

Colour map

What are the doppler shifts coded according to

A

Which is the most ideal box steering

Amplifies the doppler shifted echoes

What does colour gain do

Overwrite soft tissues

What does over gain do

Displays poor colour filling

What does under gain do

Range of doppler doppler shifts that can be displayed

What does colour scale determine

PRF

What is the colour scale also known as

Doppler shifts exceed the NyQuist limit

When does aliasing occur

1/2 the PRF

What is the nyquist limit

False

T/F: you can see colour separation when the colour flow is aliasing

Removes low doppler shifts

What does the colour wall filter do

Increase

Do you increase or decrease the colour wall filter if you want to remove low doppler shift noise

Decrease

To you increase or decrease the colour wall filter if you want to display low doppler shifts

Penetration

Lower frequency has better ________________

Resolution

Higher frequency has better ___________________

Amplitude of blood flow

What does power doppler colour code

More sensitive to slow flow and less angle-dependent

What are the advantages of power doppler

Very motion sensitive and may not display directional information

What are the disadvantages of power doppler

Trickle flow and tortuous vessels

What is power doppler used to assess

Spectral doppler with range resolution, can determine at what depth we would like to sample

What is pulsed doppler

One crystal is used to fire and then listens for returning echoes

Explain what is happening to the crystals in pulsed doppler

Velocity

What is the y-axis

Time

What is the x-axis

Amplitude

What is the z-axis

False

T/F: the baseline should be centred for pulsed doppler

Spectral broadening

What does a large sample volume increase

Increase SPL (ring time)

Increasing the size of the sample volume will:

True

T/F: aliasing is never useful in pulsed doppler

Optimize baseline and increase the scale

What are the two option to fix aliasing

Align with the jet

How should you adjust the angle correct is there is an eccentric flow jet

Amplifies the doppler-shifted echoes and affects the brightness of spectral display and waveform

What does doppler gain do

Removes low doppler shifts

What does the doppler wall filter do

Sound waves that are emitted continuously from one crystal and the reflected sound is continuously received by a second crystal

What is continuous wave doppler

False

T/F: there is still a limit to the velocities that can be detected by continuous wave Doppler

True

T/F: there is no range resolution or 2D image with continuous wave doppler

Zone of sensitivity

Where does continuous wave doppler sample from

Tunica intima, media, and adventicia

What are the 3 layers of vessels

Tunica intima

What is the innermost layer of vessels consisting of endothelial cells

Tunica media

What layer of vessels is made up of smooth muscle cells

Tunica adventitia

What layer of vessel is consisting of connective tissue, nerve fibres and small vessel capillaries

Tunica media

What layer of vessels is the thickest

Tunica adventitia

What lay of vessels does vasa vasorum originate in

Small vessel capillaries

What are vasa vasorum

Endothelial lining

What is 1

Intima

What is 2

Media

What is 3

Adventicia

What is 4

Stopcocks

Arterioles are the ___________ of the vascular system

Resistance

The arterioles are the main providers of ___________ to blood flow within the vascular system

All arteries except the aorta and major branches

What does small and medium sized arteries include

True

T/F: small and medium sized arteries are more elastic and fibrous than arterioles

Aorta and its largest branches

What does large elastic arteries include

Large amount of elastic fibres and less smooth muscle cells

Describe the composition of the walls of large arteries (aorta and its branches)

Size

What are arteries classified according to

Four

How many vessels supplies the brain

2 ICA's and 2 vertebral arteries

What 4 arteries supply the brain

Brachiocephalic, LT cca, and LT subclavian (arteries coming off the aortic arch)

What supplies the central nervous system

Brachiocephalic, LT CCA, LT subclavian

What are the 3 branches of the aortic arch

Slightly posterior from the arch to the right side of the neck

Describe the path of the Brachiocephalic artery

Innominate artery

What is another term for the Brachiocephalic artery

Rt CCA and rt subclavian artery

What does the innominate artery branch into

Upper border of the right sternoclavicular junction

Where does the Brachiocephalic artery branch into the RT CCA and RT Subclavian artery

Left sternoclavicular joint

What does the LT CCA pass underneath after ascending from the aortic arch

False

T/F: the common carotid arteries have a lot of branches coming off them as they travel toward the brain

Internal and external carotid arteries

what does the common carotid artery split into?

Upper border of the thyroid cartilage

Where does the cca divide into internal and external carotids

Aorta

What is 1

Innominate

What is 2

LT CCA

What is 3

LT subclavian

What is 4

RT subclavian

What is 5

RT CCA

What is 6

ECA

What is 7

ICA

What is 8