Understanding Hemodynamics Flashcards
Transverse plane
Divides the body into top and bottom
Short Axis
Sagittal
Right and left sections
Longitudinal
Frontal/coronal
Plane divides the body into front and back
Arm
Shoulder to elbow
Forearm
Elbow to Wrist
Upper extremity
Whole arm limb
Lower extremity
Leg
Thigh
Hip to knee
Leg
knee to ankle
Medial
Towards the center of the body
Lateral
Away from the center of the body
Proximal
Closer to the point of attachment
Distal
Further away from the point of atatchment
Cephalad
Towards the head
Caudal
Towards the feet
Superior
Upper, towards the head
Inferior
Below, towards the feet
Superficial
closer to skin
Deep
Farther down from the skin
Anterior
Towards the front of the body
Beam
An ultrasound emitting from a transducer
Plaque
Atherosclerotic material builds up in the walls of the arteries, causing most arterial problems
Lumen
Space inside a vessel, open part of a vessel through which blood flows
Stenosis
Narrowing of a vessel, usually of an artery, usually caused by atherosclerotic plaque
Bifurcation
The point at which the vessels divide or branch
what bifurcation is a common site for stenosis
Common carotid artery bifurcation
Collateral circulation
alternate pathways of blood flow that become functional in the event of arterial or venous obstruction
Embolus
An object traveling through circulation that may lodge in a vessel and cause occlusion
Several types: Air, thrombus, fat, etc
Hemodynamics
Study of blood flow characteristics
Doppler effect
A shift in frequency caused by motion
Doppler flow blood studies ultrasound is bounced off moving red blood cells; frequency of the ultrasound waves is shifted by the movement of the blood
Continuous-wave Doppler
An instrument that continuously transmits Doppler ultrasound with one crystal and continually receives with another crystal
Pulsed-Wave Doppler
Doppler ultrasound sent out in discrete bursts/pulses
Sample Volume (Gate)
A discrete area of flow assessed with pulsed Doppler. Can be adjusted as well as depth and location along doppler beam
Doppler Angle
The angle of the Doppler beam with respect to the direction of the blood flow
Angle of Incidence
what is the optimal angle for vascular scanning
45-60 degrees
past 60 leads to errors in velocity measurement
what angle gives the maximum frequency shift?
zero degrees (blood headed straight towards/away from the transducer)
Spectral Analysis
Return Doppler signal is broken down into component frequency shifts and amplitudes at those frequencies
Velocity
Speed of the blood, calculated from the Doppler frequency shift and the Doppler angle with respect to flow direction
what units is velocity expressed in?
Centimeters or meters per second
Peak Systolic/end-diastolic frequencies/velocities
Common measurements of the spectral waveform,
Where is the peak systolic measurement taken?
The highest point in the waveform
Where is the end-diastolic measurement taken?
Just prior to the systolic upstroke
Color flow imaging
Display of blood flow based (usually) on frequency shifts contained from a large area instead of from just one sample volume (as with spectral doppler)
Gain
Control on the scanner that allows an increase in the strength of the return signal being displayed
Proximal Limit/Distal limit
Farthest possible point toward or away from the heart or point of origin
Plaque
Singular, usually a commodity
Atheroma
collection of material, atheroma is used the same way as plaque
Calcific, dense
Characteristic features of certain types of plaque
Show up as bright echoes in the lumen
Dense plaque: no acoustic shadowing
Calcific plaque: Does create acoustic shadowing
Soft, fibrous
A characteristic feature of certain types of plaque
Soft, fibrous plaque creates darker echoes than dense/calcific plaque
Intimal Thickening
Thickened walls along the artery, looking a bit like very minimal atheroma
Minimal, mild, moderate, moderately severe, severe
Gradations of carotid stenosis
Circumferential
Around the entire circumference of the vessel, as opposed to plaque that lies on one side of the wall
Extensive
plaque along a lengthy segment of the artery
Scattered/diffuse
Plaque found at several levels in the artery
True lumen vs. residual lumen
the actual wall of the vessel versus the remaining opening through which blood continues to flow
Homogenous vs heterogenous
All of one consistency versus different consistencies or materials used to describe plaque
Smooth vs irregular
used to characterize the surface appearance of plaque
Crater/Crater-Like in appearance
The shape is most suggestive of ulceration of plaque, scooped-out appearance
Occulsion
Complete blockage
Laminar
orderly, nonturbulent flow`
Sharp vs damped
used to characterize the sound of the Doppler signals as well as the shape of the waveforms
Multiphasic vs monophasic
an issue in the extremity arteries
What is the normal peripheral flow
Multiphasic
what does monophasic suggest
suggest a great deal of energy has been damped out of the flow
Antegrade vs retrograde
flow in the expected direction versus flow in the opposite direction
Turbulence, spectral broadening, disturbed flow, window filling, gross turbulence
all used to characterize various degrees of flow disturbance as reflected in the spectral analysis
elevated velocities (peak systolic and end-dystolic) accelerated flow through the stenosis
used to describe flow through a hemodynamically significant lesion
Aliasing
Wrappng around of the spectral waveform that can result from high velocity blood flow
what does aliasing suggest?
severe stenosis
Patent and compressible (with light/moderate pressure)
characteristics of normal veins
coapt
to meet or join
Chronic vs acute thrombosis
old versus new thrombosis
Recanalized
having formed a channel of flow through a thrombus suggestive of an older clot maybe partial (small residual lumen and irregular walls) or nearly complete (just a brightly echogenic flap left behind)
Tail
A free-floating proximal end of a thrombus, suggesting poor attachment and is probably acute (not chronic)
Nonocculsive
Obstructed but not totally blocked
No evidence of DVT
Phrase for reports
Antegrade vs retrograde flow
Forward or reverse flow (issue with color imaging)
Map
Assignment of colors for direction and velocity/frequency shift
Aliasing (color)
Vecoloties exceed the PRF and wrap around the opposite color on the display
Mosaic
Mottled appearance created by turbulent flow-many directions and velocities of flow, creating many colors
Jet
A localized area of high velocity flow through and exiting a stenosis
