Echo Doppler Basics Flashcards
6 things Doppler asses in echo
flow through valves
pulmonary venous flow into LA
hepatic venous flow
SVC/IVC flow
aortic flow
differentiate tissue from blood
normal valve velocities:
TV ≤ ____
PV ≤ ____
MV ≤ ____
AV ≤ ____
1
1
1.3
2
valvular stenosis results in ____ flow velocities
increased
colour (qual/quantitative, give us what)
qualitative
gives us a good idea about regurg, stenosis, etc.
pulsed wave spectral (PW) (qual/quantitative, give us what)
quantitative
give us spectral signal from a specific sample volume (spot)
continuous wave spectral (CW) (qual/quantitative, give us what)
quantitative
gives us a spectral signal from an entire line of scan
CW spectral is used for _____ velocities
very high
order of images
- 2D/M mode (+/- zoom)
- colour
- spectral (PW or CW)
do we ever invert colour for echo
no
colour doppler is a ____ wave technique and ____ subject to aliasing
pulsed
is
where is aliasing normal
where higher velocities are (ex. LVOT/AV)
antegrade = _____ flow
normal
normal flow in echo has a normal flow _____ and flow ___
direction
velocity
colour doppler is a ____ doppler technique with many tiny sample volumes placed in the colour box = _____ FR
PW
lower
3 advantages to colour doppler
sensitivity: can detect small amounts of blood flow
ROI: anatomic + hemodynamic info in one image
laminar vs turbulent
PFO
patent foramen ovale
hole in interatrial septum
2 disadvantages to colour
aliasing: at high velocities
directional ambiguity: perpendicular = flow is many colours
does stenosis show aliasing
yes
does regurg show aliasing
will show a bit right at the valve and beyond
do shunts show aliasing
yes for the most part due to a large difference in pressures = high velocity
colour imaging adjustments (4)
gain
scale
box size
centering
what is a shunt
connection that doesn’t normally belong there
overgaining will cause:
undergaining will cause:
bleeding
missed data
gain is adjusted with each new patient or when ____ has been majorly adjusted
scale
does a large atrial septal defect show aliasing
no
gain for colour doppler should be
just below speckle
do most patients need scale changed
no
scale should match ___
flow
if flow is average velocity, scale should be ___
not changed
if flow is a high velocity, scale should be ____ (ex of where)
increased
AC, PV, Ao
if flow is low velocity, scale should be ___ (ex of where)
decreased
pulmonary veins, IVC, IAS, hepatic veins)
box size for echo colour should be ____ and ____
long and lean
the ____ of the colour box has a large effect on the frame rate
width
frame rate for echo must be ____
20 or more Hz
box should be wide enough to:
cover width of entire valve
box should be narrow enough to:
narrow enough to maintain FR
why is centering colour box important
moves with cardiac cycle so make sure it is always over ROI, ensure some room around ROI
spectral doppler adjustments (5) (PW or CW)
alignment
baseline
scale
gain
sweep speed
the ideal doppler angle for echo is ___
0 degrees (or 180 if flow is going away)
we must try to line up our flow to be ____ with our beam to achieve accurate doppler imaging
parallel
baseline should sit _____ from either the top or bottom, leaving room for the _____ flow pattern
1/4-1/3
dominant
scale should be low enough that there is no ____
wasted space
doppler signal should be displayed as _____ as possible without _____ in either direction (scale)
large
aliasing
scale should be ___ enough to leave a little room around the signal
high
spectral gain should ______ noise from behind signal (background = ____, PW has ______)
eliminate
black
black envelope
sweep speed should be set to show _____ full beats
3
_____ the sweep speed for higher HR
increase
_____ sweep speed for a low HR
decrease
faster sweep speed = _____ waveform
stretches
sweep speed is represented in ____
mm/sec
spectral for TR should have a TV scale _____ baseline set to ______
below
240cm/sec
why don’t we focus above the baseline for TV
because TV stenosis is very rare in adult population
PW vs CW (2)
PW has pulses from a specific site and is used for lower velocity signals
vs
CW samples entire scan line and is used for high velocity signals
CW often has ______ due to the many different velocities seen along the scan line
spectral broadening
PW doppler 4 advantages
range specificity
adjustment of sample volume size/position
able to map velocities at any point in the heart
2D display guidance
PW 2 disadvantages
inability to measure high velocities due to aliasing
limited by the speed of sound in tissue and PRF
PW can’t measure velocities above ___
2.0-2.5 m/s
nyquist limit = ____ PRF
1/2
4 ways to overcome aliasing (Nyquist limit)
adjust baseline
decrease sample depth = increase PRF
switch to high PRF
switch to CW doppler
what is high PRF setting
increased PRF by increasing the number of sample volumes
2nd pulse emitted before 1st returns
high PRF setting leads to
range ambiguity
high PRF setting is used to sample ______ velocities at _____
high
specific sites
HOCM
hypertrophic obstructive cardiomyopathy
main advantage to CW
high velocity range
main disadvantage to CW
no range resolution (unable to be sure that a velocity is coming from a specific location)
TDI stands for
tissue doppler imaging
TDI assesses the ______
movement of myocardial tissue
TDI signal is of greater ______ (____)
intensity
bright
TDI had a _____ velocity compared to blood flow velocities
lower
TDI should resemble a mirror image of ____ velocity profile and on a ____ scale
MV
Lower
TDI consists of ____ upward wave(s) and ___ downwards wave(s)
one
two
in TDI, the machine is able to change settings automatically to optimize tissue doppler waveforms (T/F)
T
4 advantages to TDI
easily reproducible
provides systolic and diastolic info in one waveform
can be performed on every patient including TDS patients
less volume dependant than MV inflow (preload)
4 disadvantages to TDI
angle dependant
filter settings can vary widely between machines
gain settings can be too low on phillips
not helpful when patient has: prosthetic valves, MAC, mitral annular ring
MAC
mitral annular calcification
how to do TDI
place cursor at annulus
click TDI button on touch screen
2 doppler measurements
peak velocity (caliper)
velocity time integral (VTI) (tracing)
VTI is a representation of how far the blood flow would have ____ in that time (represented in ___)
travelled
cm
peak velocity measures (2)
peak velocity
maximum (peak) instantaneous pressure gradient
do not include ____ on peak velocity measurements
feathering
VTI measures what 5 things
peak velocity (m/s)
mean velocity (m/s)
VTI (cm)
max PG (mmHg)
mean PG (mmHg)
minimize the “beard” by ____ the reject and ____ the compression
increasing
decreasing
