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Physics > Lecture 23 Part 3 > Flashcards

Lecture 23 Part 3 Flashcards

1
Q

Analyzing the waveform

A

To assess for normal blood flow and pathology

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2
Q

Ateries

A

Pulsatile, higher velocity waveforms

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3
Q

Veins

A

Phasic, lower velocity waveforms

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4
Q

We assess the _______ portion and the _____ portion

A

Systolic

Diastolic

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5
Q

High resistance

A

ECA, extrmities
Quick upstroke
Low diastole

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6
Q

Low

A

ICA/ CCA, blood hungry organs
Vasodilation
Slow upstroke
Higher diastole

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7
Q

Use what rule to assess area of stenosis

A

Continuity rule

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8
Q

Q=

A

Q= Vavg x A

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9
Q

In areas of stenosis

A

Decreased area causes increase in velocity

Surpasing reynolds # = turbulence

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10
Q

Spectral broadening related to

A

Turbulence

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11
Q

Specrtal broadening wider range of spectra = _____________ of shifts

It is narrowing the ________

A

More variety of shifts

Narrowing the window

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12
Q

Most obvious reason to spectral broadening

A

Stenosis

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13
Q

Erroneous spectral broadening you _____ the gain

A

Increase

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14
Q

In erroneous spectral broadening tortuous vessels will also give

A

A large variety of signals i

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15
Q

In erroneous spectral broadening you increase

A

Sample volume size

Catching multiple vessels at once

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16
Q

Analyzing the wave form we also look at _____ and _____ waveforms

A

Pre and post stenosis

17
Q

Clue to whats downstream

A

Increased resistance means possible distal stenosis

Spectral has waves more clear and pushed together in high resistance

18
Q

Upstream clues are

A

Tardus parvus wavefomr

19
Q

Tardus parvus waveform is

A

Very slow rounded wave forms

Suggests proximal stenosis

20
Q

Monophasic wave form

A

Suggests possible upstream stenosis

Thick single waveforms

21
Q

Quantitative index

A

Acceleration time

22
Q

Acceleration time suggests

A

Resistance

Can also show tardus parvus

23
Q

Spectral limitations (4)

A

Sonographer skill
Movement
Range gated to a specific depth
Aliasing

24
Q

Fixing the aliasing (4)

A

Adjust the baseline
Lower the operational freq
Increase your doppler angle —> lowers all doppler shift
Increase the PRF (increases Nyquist), allows for higher doppler shift

25
Q

CW doppler

A

Occasionally used
Two transducer elements - one to send, one to recieve
Oscillator produces a voltage making continuous wave

Sample volume is the large overlapping are of transducer

26
Q

Continuous wave and pulsed wave

A

Often built in the same system
Can toggle back and forth
Often use a “pencil” probe

27
Q

CW cannot

A

Alias

Aliasing happens becasue shift is more than the Nyquist limit
Nyquist limit = half PRF

No PRF in continusous wave

Therefore can pick up very high max values without aliasing

28
Q

CW limitations

A

Large sample volume - cant tell exactly where its coming from = poor rangle resolution

PW has excellent range resolution

Physics (32 decks)

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