Lecture 23 Part 3

Question 1

Analyzing the waveform

Answer 1

To assess for normal blood flow and pathology

Question 2

Ateries

Answer 2

Pulsatile, higher velocity waveforms

Question 3

Veins

Answer 3

Phasic, lower velocity waveforms

Question 4

We assess the _______ portion and the _____ portion

Answer 4

Systolic

Diastolic

Question 5

High resistance

Answer 5

ECA, extrmities
Quick upstroke
Low diastole

Question 6

Low

Answer 6

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

Question 7

Use what rule to assess area of stenosis

Answer 7

Continuity rule

Question 8

Q=

Answer 8

Q= Vavg x A

Question 9

In areas of stenosis

Answer 9

Decreased area causes increase in velocity

Surpasing reynolds # = turbulence

Question 10

Spectral broadening related to

Answer 10

Turbulence

Question 11

Specrtal broadening wider range of spectra = _____________ of shifts

It is narrowing the ________

Answer 11

More variety of shifts

Narrowing the window

Question 12

Most obvious reason to spectral broadening

Answer 12

Stenosis

Question 13

Erroneous spectral broadening you _____ the gain

Answer 13

Increase

Question 14

In erroneous spectral broadening tortuous vessels will also give

Answer 14

A large variety of signals i

Question 15

In erroneous spectral broadening you increase

Answer 15

Sample volume size

Catching multiple vessels at once

Question 16

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

Answer 16

Pre and post stenosis

Question 17

Clue to whats downstream

Answer 17

Increased resistance means possible distal stenosis

Spectral has waves more clear and pushed together in high resistance

Question 18

Upstream clues are

Answer 18

Tardus parvus wavefomr

Question 19

Tardus parvus waveform is

Answer 19

Very slow rounded wave forms

Suggests proximal stenosis

Question 20

Monophasic wave form

Answer 20

Suggests possible upstream stenosis

Thick single waveforms

Question 21

Quantitative index

Answer 21

Acceleration time

Question 22

Acceleration time suggests

Answer 22

Resistance

Can also show tardus parvus

Question 23

Spectral limitations (4)

Answer 23

Sonographer skill
Movement
Range gated to a specific depth
Aliasing

Question 24

Fixing the aliasing (4)

Answer 24

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

Question 25

CW doppler

Answer 25

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

Question 26

Continuous wave and pulsed wave

Answer 26

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

Question 27

CW cannot

Answer 27

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

Question 28

CW limitations

Answer 28

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

PW has excellent range resolution