Shared Flashcard Set

Details

103
Carotid/Echo Doppler
53
Medical
Professional
11/11/2011

Additional Medical Flashcards

 


 

Cards

Term
What does the ECA do?
Definition
Perfuses the face and scalp
Term
What does the ICA do?
Definition
Perfuses the brain and eyes
Term
What branch off the carotid artery is medial?
Definition
The ECA
Term
What branch off the carotid artery is lateral?
Definition
The ICA
Term
What does the CCA do?
Definition
Supplies both the ICA and ECA
Term
What is the function of a duplex study?
Definition
Ultrasound image for anatomy and doppler for physiology
Term
What are the characteristics of ICA flow?
Definition
low-resistance with lots of diastolic flow. "Whoosh" sound
Term
What are the characteristics of ECA flow?
Definition
Somewhat higher-resistance than ICA with less diastolic flow. Sharp sound.
Term
What are the characteristics of CCA flow?
Definition
Elements of both ICA and ECA since it supplies both.
Term
What is the Doppler principal?
Definition
Frequency is shifted by motion.
Term
What is the Doppler equation and what are the influences on freqency shift?
Definition

Δf = 2f0V(cosθ)/c

 

Δf=frequency shift

is enfluenced by:

 

f0=emitted frequency

V=velocity

cosθ=angle

c=velocity of waves in the medium (tissue)

Term
Considering the Doppler Principle, does a positive shift in frequency suggest higher velocity than a negative shift?
Definition
Yes, because frequency shift has a direct relationship with velocity.
Term
What is spectral analysis?
Definition

 Assign a pixel to each separate shifted frequency. Pixel is brighter or darker depending on the strength of the echo at that frequency.

 

The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform.

Term
What are the 3 elements (kinds of information) on the spectral display?
Definition
1. Time as demonstrated on the X axis
2. Frequency shift (velocity) as demonstrated on the Y axis
3. Echo strength for a given frequency shift as demonstrated with pixel brightness.
Term
What does a bright pixel signify?
Definition
Lots of blood moving at a set velocity.
Term
What does a dark pixel signify?
Definition
Not much blood moving at a set velocity.
Term
What Doppler angles are ok and why?
Definition
50-60°, For trade consistency
Term
How do you produce good Doppler angles?
Definition
Rock the beam or steer the angle.
Term
How do you tell whether flow is toward the beam or away?
Definition
Visualize a perpendicular line to the beam direction. If the flow direction is above that perpendiclar line, flow is more toward the beam than away. If flow direction is below the perpendicular line, then flow is more away than toward. Steer the beam to the right so flow is toward the beam. Steer the beam to the left so flow is away from the beam.
Term
What should you ask yourself before freezing a waveform for measurement?
Definition
1. Are the waveforms clear? 2. Are the walls clear? 3. Is the angle-correct cursor lined up with the walls?
Term
What do you always do after freezing an image but before measuring?
Definition
Double-check the angle correction. The ends of the cursor should be parallel to the walls.
Term
What do you measure on a Doppler waveform?
Definition
Peak systolic volume and end diastolic volume
Term
What Peak Systolic Volume (PSV) suggests hemodynamically significant stenosis of the ICA?
Definition
125 cm/sec = >50%
Term
What End Diastolic Volume (EDV) suggests really severe (>80%) stenosis?
Definition
140 cm/sec
Term
What End Diastolic Volume (EDV) suggests >70% stenosis?
Definition
100 cm/sec
Term
What governs diastolic flow character?
Definition

Diastolic flow character is governed by distal resistance.

 

"If it's a low-resistance vascular bed (e.g., the brain, or any organ), then there will be lots of forward flow during diastole. If high-resistance (e.g., the lower extremities), then there will be reversal of flow during diastole. An intermediate-resistance bed (e.g., the face/scalp perfused by the ECA, or the upper extremity) will be sharper but still may have a bit of diastolic flow." ~Ridgway~

Term
[image]
A
Definition
Apex
Term
[image]
B
Definition
RV
Term

[image]

C

Definition
LV
Term
[image]
D
Definition
IVS
Term
[image]
E
Definition
TV
Term
[image]
F
Definition
MV
Term
[image]
G
Definition
IAS
Term
[image]
H
Definition
RA
Term
[image]
I
Definition
LA
Term
[image] J
Definition
Anterior Wall a.k.a. Free Wall
Term
[image]
K
Definition
LV Lateral Wall
Term
On an Apical Doppler, where should you place the gate (sample volume) for stenosis?
Definition
For evaluating stenosis, get the gate at the tips of the open leaflets. (AV valves for diastole and SL valves for systole)
Term
On an Apical Doppler, where should you place the gate (sample volume) for regurgitation?
Definition
For evaluating regurgitation, get the gate behind the leaflets and check for flow when valve is closed. (AV valves for systole and SL valves for diastole)
Term
What is normal velocity values for the aortic valve?
Definition
1.7 m/sec
Term
What is normal velocity values for the mitral valve?
Definition
1.2 m/sec
Term
What is normal velocity values for the pulmonic valve?
Definition
0.9 m/sec
Term
What is normal velocity values for the tricuspid valve?
Definition
0.7 m/sec
Term
Where within the heart are velocities lower and why?
Definition
Right heart; pressure gradient is not as high
Term
How do you orient yourself while doing a carotid scan and Doppler?
Definition
Feet are always to the right of the screen
Term
How do you orient yourself while doing an apical 4-chamber and 5-chamber cardiac scan and Doppler?
Definition
The right heart is on the left and the left heart is on the right with the apex at the top and the base at the bottom.
Term
Where do you set the baseline while doing a Doppler on AV valves?
Definition
Since blood flow is toward the beam, the Doppler waves will be above the baseline; therefore, set the baseline low on the scale.
Term
Where do you set the baseline while doing a Doppler on SL valves?
Definition
Since blood flow is away from the beam, the Doppler waves will be below the baseline; therefore, set the baseline high on the scale.
Term
What are the characteristics of AV valve Doppler images?
Definition
AV valve have a M-shape characteristic somewhat like M-mode due to primary passive filling and secondary active filling with the atrial kick.
Term
What are the characteristics of SL valve Doppler images?
Definition
SL valves have a single-phase waveform.
Term
What do you measure for cardiac Doppler?
Definition
Peak velocities
Term
If velocities are higher than WNL, what does that signify?
Definition
stenosis
Term
How is the pressure gradient across a valve calculated?
Definition

Bernoulli's equation

V1A1=V2A2

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