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0

What is duplex imaging?

integrating different forms of Doppler

1

What are the different modes to combine together?

2D

gray scale

B-mode

plus:

color doppler
pulsed doppler - spectral doppler

2

What is flow analysis?

is there flow?

the presence or absence of flow

3

how do you determine Portal vein?

echogenic wall

traverses across the liver - hepatic veins go up into the liver

4

What is important about the doppler curser?

called the gate or sample volume

proper placement is important

in the center of the vessel

5

How do you tell the direction of flow?

color map

above the black line = toward the transducer red

below black line = away from the transducer blue

6

what does hepatopetal mean?

toward the liver

this is the way you want to the blood to flow

7

what does hepatofugal mean?

away from the liver

this is the wrong way for the blood to flow

8

What is spectral display low flow?

Non resistive - low

high diastolic

constant perfusion

9

what is spectral display high flow?

Resistive - high

little diastolic or reversed flow

10

What is spectral display?

time (on the x axis)

Doppler shift frequency is on the vertical y - axis

gray scale quanitity of blood (z)

11

What is the computer computing with spectral display?

Doppler frequency shift measured in Hz

the machine changes it to speed

12

what is the pulsatility index (PI)?

a measure of the variability of blood velocity in a vessel, equal to the difference between the peak systolic and minimum diastolic velocities divided by the mean velocity during the cardiac cycle.

13

What is plug flow?

pattern of blood flow, typically seen in large arteries, in which most cells are moving at the same velocity across the entire diameter of the vessel

14

What is turbulent laminar flow?

Abnormal

chaotic patterns

15

What are some techniques for using Doppler?

fasting

suspend respirations

parallel to flow 0 degrees

angle less than 60 degrees

16

What changes about the SMA after you eat concerning Doppler?

high resistance before

low resistance after

see slides for visual

17

What is RAS?

renal artery stenosis

18

what is tardis parvis?

when you lose the point on the doppler wave

19

Where would you find non resistive low flow confirmed by spectral display?

internal carotid,

hepatic

renal

20

Where do you find resistive high flow confirmed by spectral doppler?

supply to organs that do not need constant blood supply

external carotid

iliac

brachial arteries

21

How is blood velocity calculated?

by frequency shifts

22

How do you read a spectral display?

The peak is the systolic and the end is the diastolic

23

What is the formula for the resistive index?

RI = Peak systolic velocity - lowest diastolic velocity/ peak systolic velocity

RI = S-D/S

24

What is resistive index?

peak systole is compared with minimum diastole to quantify a vessels impedance

25

What picture does typical plug flow give you on the spectral doppler?

a "clear window" under systole

26

What needs to be present for the volume of blood flow to be calculated?

plug flow must be present

27

What is parabolic flow?

velocity higher in the center of the laminar layers and decreases at the vessel wall

28

What are the doppler flow patterns for the Aorta?

High systolic peak

varies at different levels

becomes triphasic closer to the legs

29

What does triphasic mean?

having or occurring in three phases...seen and heard

30

What is the Doppler flow pattern of the celiac axis?

Some spectral broadening

no change related to meals

31

what is spectral broadening?

broadening of the spectral lines (makes them thicker)

32

What are the doppler flow patterns for the hepatic artery?

more spectral broadening is seen during systole and diastole

33

What are the doppler flow patterns in the splenic artery?

turbulence

prone to aneurysm

34

What are the Doppler flow patterns in the SMA?

highly resistive in the fasting state

low resistive in the post prandial state

SMA occulsion is possible

35

What are the Doppler flow patterns for the Renal arteries?

Low resistive

high diastolic flow

spectral broadening

renal artery stenosis possible

36

What is the doppler flow pattern in renal artery disease?

high velocity jet shown in the right renal artery

spectral waveform shows increased velocity of more than 4 m/sec

37

How do you improve color images?

increase the PRF or scale

38

What can cause aliasing of the spectral waveform?

if the frequency shift is too high for the PRF setting

39

What does aliasing of the spectral waveform mean?

a portion of the waveform is cut off and displayed below the baseline

40

How do you fix aliasing of the spectral waveform?

by raising the PRF and lowering the baseline

this allows the peak velocity to display correctly and an accurate velocity to be obtained

41

What does Power Doppler NOT demonstrate?

Direction of flow

42

What are the doppler flow patterns for a renal transplant?

normal transplants have a diastolic flow that is 30-50% of systole

43

what does rejection of a transplanted kidney do to the doppler flow patterns?

decreases or reverses the diastolic flow

44

What does an RI of 0.7 or less indicate in a renal transplant??

indicates good perfusion

45

What does an RI of 0.7-0.9 indicate in a renal transplant?

possible rejection

46

What does and RI of 0.9 or greater indicate in a renal transplant?

indicates probable rejection

47

What is the Doppler flow pattern in the Renal Vein?

variable flow

tumors make obstructive flow

48

What pathology could you possibly have if you have a complex waveform in the hepatic veins?

could be reflecting reflux from the right atrium

49

What kind of flow pattern does the Portal vein have?

continuous flow pattern

hepatopetal (toward the liver)

50

What might cause HTN in the portal vein?

intrinsic liver disease

obstruction

51

what is Budd Chiari?

Thrombosis of the hepatic veins

veins appear reduced in size

may contain echogenic thrombus

52

What are some things you might find with portal vein hypertension?

Dilated portal, splenic and SMV

varices

Splenomegaly

Ascites

patent umbilical vein

abnormal liver

53

What happens to the portal vein's response to respiration when there is portal vein hypertension?

there is a diminished response

54

What does portal vein hypertension do to the hepatic and splenic arteries?

it dilates them

55

What is the definition of Portal Hypertension?

acute or chronic hepatocellualr disease can block the flow of blood throughout the liver, causing it to back up into the hepatic portal circulation. This causes the blood pressure in the hepatic circulation to increase

56

When and why do collateral veins form?

when there is portal hypertension, collateral veins are formed in an effort to relieve the pressure.

they connect to the systemic veins

57

Where do most collateral (varicose) veins occur?

in the esophagus

stomach

rectum

58

What happens if varicose veins in the esophagus, stomach or rectum rupture?

massive bleeding that may result in death

59

How does pulse repetition frequency (PRF) affect Doppler?

PRF allows one to record lower velocities as the PRF is lowered.

as PRF is increased, the lower velocities are filtered out to record only the higher velocity signal

60

How is PRF changed on the US machine?

with the scale control on the doppler panel

(look at the color bar on the lt side of the monitor, the PRF will change as the "scale" on the doppler control is changed)

61

What kind of PRF is needed in order to doppler flow in the hepatic venous system?

a lower PRF is necessary to record the flow pattern because flow in the hepatic venous system is low.

As the flow increases beyond 40cm/sec the PRF should be increased to prevent aliasing

62

If PRF increases what happens to imaging depth?

it also increases

if imaging depth decreases, PRF also decreases

63

What helps eliminate "noise" or low level Doppler shifts seen within the vessel?

Wall filters

64

Doppler angle correction should be less than _______ to display the peak spectral velocity.

60 degrees

65

What is the doppler flow in the splenic vein?

flow is reversed in the splenic vein...away from the liver

66

What are the sonographic indications that cavernous transformation of the portal vein has occured?

extrahepatic portal vein is not visualized

high level echoes producedd by fibrosis are present in the porta hepatis

multiple tubular structures are present in the porta hepatis, representing periportal collaterals

67

When there is portal venous hypertension what does Doppler determine?

whether portal flow is hepatopetal or hepatofugal

68

What causes portal venous hypertension?

caused by the obstruction of the portal vein, hepatic vein, IVC

prolonged congestive heart failure

69

How is portal blood diverted when there is portal venous hypertension?

in a hepatofugal direction

through collateral venous pathways

with the formation of multiple portosystemic anastomoses

70

When portal venous hypertension is present what happens to the velocity of blood flow?

Portal vein shows low velocity

71

What vein gives the definitive diagnosis of Portal venous hypertension?

Patent paraumbilical vein

72

Typical portal hypertensive venous flow varies... true or false?

True

73

What two pathologies most frequently cause portal venous hypertension?

cirrhosis

obstruction of portal venous radicles by fibrosis and regenerating nodules

74

What do we see happen on US to the portal, splenic and superior mesenteric vein when there is portal venous hypertension?

These vessels are dilated

75

When there is portal venous hypertension what happens to the spleen?

splenomegaly with dilated splenic radicles

76

What does the liver look like when there is portal venous hypertension?

small liver with irregular surface

or

larger liver with abnormal texture

77

What does TIPS stand for?

Transjugular Intrahepatic Portosystemic Shunt

78

What are spontaneous intrahepatic portosystemic venous shunts?

rare disorders that describe abnormal connections between branches of the portal vein and systemic veins