Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Sonography Principles And Instrumentation > Lecture 16 > Flashcards

Lecture 16 Flashcards

1
Q

DOPPLER SHIFT=

A

REFLECTED FREQ - INCIDENT FREQ.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

DOPPLER SHIFT EQUATION

A

DS = 2 x SPEED OF REFLECTOR x OPERATING FREQ x COSINE/ PROPAGATION SPEED

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

“2” IN DS EQUATION:

A

INITIAL ENCOUNTER W/SOUND WAVE AND REDIRECTION TO SOURCE.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

OPERATING FREQUENCY IS ______ RELATED TO MAGNITUDE OF SHIFT.

A

DIRECTLY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

VELOCITY OF REFLECTOR _______ PROPORTIONAL TO DOPPLER SHIFT.

A

DIRECTLY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

THE GREATER THE ANGLE (TOWARD 90 DEGREES) THE ______ THE COSINE.

A

SMALLER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

COSINE OF 90 DEGREES

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

DOPPLER SHIFT FREQUENCY IS ___________ TO VELOCITY OF FLOW.

A

PROPORTIONAL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • SENDS AND RECEIVES SOUND CONTINUOUSLY
  • 2 ELEMENTS
  • AUDIO AND WAVEFORM PRESENTED
  • MEASURES HIGH VELOCITY FLOW ACCURATELY
  • SMALL PROBE EASY TO MANIPULATE
  • DISADVANTAGE - RANGE AMBIGUITY
A

CW DOPPLER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

DETERMINES DIRECTION OF DS

A

QUADRATURE DETECTION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

DETERMINES IF DS IS POS OR NEG.

A

BI-DIRECTIONAL DEVICE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

CANNOT DETERMINE IF DS IS POS OR NEG.

A

UNI-DIRECTIONAL DEVICE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  • 1 ELEMENT
  • DS DISPLAYED AS WAVEFORM AND AUDIBLY
  • DUPLEX SCANNING
  • RANGE RESOLUTION (ABILITY TO DETERMINE DEPTH)
  • DISADVANTAGE: ALIASING
A

PW DOPPLER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

IMPROPER REPRESENTATION OF A POS SHIFT AS A NEG SHIFT

A

ALIASING

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

ALIASING OCCURS:

A

-WITH UNDERSAMPLING
-SAMPLING FREQ MUST = PRF
(PRF MUST BE 2x DS FREQ.)
-NYQUIST LIMIT EXCEEDED

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

NYQUIST LIMIT =

A

1/2 PRF

17
Q

ELIMINATION OF ALIASING:

A
  1. CHOOSE SHALLOWER SAMPLING DEPTH
  2. INCREASE VELOCITY SCALE
  3. ADJUST BASELINE SHIFT
  4. CHOOSE LOWER FREQ TRANS.
  5. USE CW INSTEAD
18
Q

SEPARATION OF MULTIPLE FREQUENCY COMPONENTS IN DOPPLER SIGNAL TO INDIVIDUAL ONES.

A

SPECTRAL ANALYSIS

19
Q

PURPOSE OF SPECTRAL ANALYSIS:

A

-PROVIDE QUANTITATIVE DATA ON DIFFERENT REFLECTORS

20
Q

SPECTRAL ANALYSIS IS ACCOMPLISHED BY:

A

FFT (FAST FOURIER TRANSFORM) PROCESSOR

21
Q

COMPLEX MATHEMATICAL PROCESS ANALYZING SIGNAL AND PRESENTING IN REAL TIME.

A

FFT (FAST FOURIER TRANSFORM) PROCESSOR

22
Q

INFO PW DOPPLER PRODUCES:

A
  • VELOCITY FLOW
  • DIRECTION OF FLOW
  • RANGE OF FREQ.
  • DURATION OF SIGNAL
  • MAGNITUDE OF SIGNAL
23
Q

QUANTITATIVE DOPPLER MEASUREMENTS RELATE TO______________________.

A

PULSATILITY OF FLOW.

24
Q

PULSATILITY INDEX:

A

PI = MAX VELOCITY - MIN VELOCITY / MEAN VELOCITY

25
Q

RESISTIVITY INDEX:

A

RI = MAX (SYSTOLIC) VELOCITY - MIN.(DIASTOLIC) VELOCITY/ MAX VELOCITY

Sonography Principles And Instrumentation (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions