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95 Cards in this Set
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Doppler waveform contour is directly related to |
Cardiac output, vessel compliance status of distal vascular bed |
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The Doppler waveform contour in a normal CCA, I CA, or ECA has a |
Brisk systolic acceleration, sharp systolic peak, and clear spectral window |
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Because the ICA supplies the brain directly it has |
The lowest peripheral resistance and shows the highest diastolic flow Velocities with forward flow throughout the cardiac cycle |
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The Doppler waveform from the CCA takes on the characteristics of both |
The Interno and external carotid arteries, As it supplies both branches |
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However about - - Of normal CCA flow volume passes through the ICA |
70%, so the CCA usually has a low resistance to flow pattern with forward flow throughout the cardiac cycle |
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The brachiocephalic artery has a higher resistance to flow pattern that reflects the same status of the multiple vascular beds that it supplies including |
The arm – high resistance The face – high resistance Brain- low resistance |
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Changes in the contour of the Doppler waveform associated with arterial disease depend greatly on |
Location of the site of isonation relative to the stenosis or obstruction |
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Call lateral pathways can influence waveform contour depending on |
The location of the stenosis relative to proximal and distal arterial branches |
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Standard Doppler principles dictate that the Doppler arterial waveform within a significant stenosis will be characterized by |
A high velocity jet |
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The waveform contour distal to a significant stenosis will be |
Dampened, with decrease flow velocity, delayed acceleration, and a rounded peak
This is sometimes referred to tardus parvus |
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The features of Doppler waveforms obtained proximal to a stenosis depend on the |
Lesion in the intervening collateral vessels |
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If collateral flow is limited and the stenosis is severe, the waveform will have |
Hi resistance pattern with low velocity or absent diastolic flow |
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The most severe stenosis, which are nearly inclusive, will produce |
The most abnormal, preclusive waveform contour known as string sign flow |
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The steel phenomenon describes |
The situation where one vascular bed draws blood away or steals from another, which tends to occur when to run off beds with different resistances are supplied by limited source |
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The degree of arterial steel depends on the severity of the stenosis and |
The resistance offered by the various downstream vascular beds |
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A latent steel describes |
Flow that is beginning to show signs of reversal, but is not yet completely retrograde |
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Hesitant waveforms possess |
A deep flow Reversal notch |
When flow pauses before progressing cephalad |
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A latent steel describes |
Flow that is beginning to show signs of reversal, but is not yet completely retrograde |
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Hesitant waveforms possess |
A deep flow Reversal notch When flow pauses before progressing cephalad |
When flow pauses before progressing cephalad |
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When the deep notch In the Doppler waveform extends below the baseline, with a portion of the flow fully retrograde during part of the cardiac cycle is known as |
Alternating or bidirectional |
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In the case of a progressive proximal subclavian artery stenosis, change in pressure gradients at the origin of the ipsilateral vertebral artery can change the ratio of antegrase to retrograde To a point where flow is entirely in the retrograde direction is called |
A complete steal |
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String sign flow is characterized by |
Blunted, somewhat resistive waveforms and is the pattern that precedes complete occlusion of the vessel |
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With string sign the patient may still undergo |
On an endarterectomy |
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With string sign the patient may still undergo |
On an endarterectomy |
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Patience with a complete occluded Vessel will not be |
Be surgical candidates |
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Decreased diastolic flow or resistive component and overall blunted appearing waveform in the extracranial ICA indicates |
A severe stenosis or occlusion in the more distal or intracranial segments |
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Aortic valve or route stenosis would generate a |
Symmetrical abnormal Doppler arterial waveform contour in the right and left carotid systems |
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Aortic valve or route stenosis would generate a |
Symmetrical abnormal Doppler arterial waveform contour in the right and left carotid systems |
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Severe stenosis or occlusion of the brachiocephalic artery creates |
Decrease pressure and waveform changes in the right CCA and subclavian artery in there distal branches |
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Severe stenosis or occlusion of the proximal, mad, or distal CCA will affect |
The Doppler arterial waveform in the remaining peripheral segments of the CCA, as well as the ICA, and ECA |
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A severe distal CCA obstruction with continued patency of the carotid bifurcation is often referred to as |
A choke lesion |
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Flow direction distal to a choke lesion depends on |
The local pressure gradients and can result in varying degrees of steel |
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Rarely, flow will reverse in the |
ICA to supply the ECA in response to unusual intracranial collateral pathways |
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Rarely, flow will reverse in the |
ICA to supply the ECA in response to unusual intracranial collateral pathways |
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When the internal carotid artery is occluded, Doppler arterial waveforms throughout the common carotid artery will be |
More resistive and more identical to the external carotid artery |
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Complete external carotid artery occlusion is uncommon due to |
Multiple branches and abundant collateral pathways |
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Low cardiac output and poor ejection fraction can affect |
Systemic arterial pressure and Doppler arterial waveform contour throughout the cardiac system |
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Low cardiac output and poor ejection fraction can affect |
Systemic arterial pressure and Doppler arterial waveform contour throughout the cardiac system |
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On unusual waveform with two prominent systolic peaks separated by a systolic Re-fraction called |
Pulsus bisferiens |
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Cardiac arrhythmias can also make interpreting Doppler waveforms difficult because |
Standard velocity criteria may not apply in the waveform contour may be altered |
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Low cardiac output and poor ejection fraction can affect |
Systemic arterial pressure and Doppler arterial waveform contour throughout the cardiac system |
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On unusual waveform with two prominent systolic peaks separated by a systolic Re-fraction called |
Pulsus bisferiens |
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Cardiac arrhythmias can also make interpreting Doppler waveforms difficult because |
Standard velocity criteria may not apply in the waveform contour may be altered |
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What are two examples of cardiac assist devices |
A ventricular assist device VAD Intra-aortic balloon pump I ABP |
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DFX of cardiac assist devices on Doppler arterial waveform contour is profound creating patterns that |
May be unrecognizable as arterial flow |
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DFX of cardiac assist devices on Doppler arterial waveform contour is profound creating patterns that |
May be unrecognizable as arterial flow |
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Flow velocity obtain from Doppler waveforms serves as |
The primary criterion for classification of stenosis severity with duplex ultrasound |
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DFX of cardiac assist devices on Doppler arterial waveform contour is profound creating patterns that |
May be unrecognizable as arterial flow |
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Flow velocity obtain from Doppler waveforms serves as |
The primary criterion for classification of stenosis severity with duplex ultrasound |
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The Doppler angle of insonation Is traditionally defined as |
The angle between the line of the ultrasound beam in the arterial wall at the site of the PW Doppler sample Volume |
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Call arterial velocity measurements should be obtained using an angle of insonation |
Of 60° or less This is accomplished by either adjusting the steering of the Doppler beam or by transducer maneuver called toe heel |
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Toe heel maneuver involves |
Slight transducer pressure at either end of the trans Duser to push a vessel into a slight angle |
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For carotid duplex scanning, a Doppler angle of 60° or less results in |
Clinically valid velocity information for the classification of stenosis severity |
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In a segment where stenosis is suspected |
Sweep the sample volume cursor to the area proximal to distal evaluating flow closely spaced intervals |
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The carotid and vertebral artery systems are connected by |
The circle of Willis at the base of brain |
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Potential collateral routes include |
Posterior – tO – anterior Side to side and extracranial to intracranial |
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When there is a severe stenosis or complete occlusion of one iCA,Velocities maybe |
Increased in the contralateral carotid system due to compensatory collateral flow |
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Compensatory flow is generally associated with |
Hey defuse increase in Flow velocity throughout the contralateral CCA and I CA, without a focal hi velocity jet or other localize flow disturbance |
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The b mode imaging and Doppler waveform for classification of carotid artery disease have been developed by |
Comparing the results of duplex scanning with gold standard imaging modalities are surgical findings |
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One of the most widely applied classification schemes for ICA stenosis was developed at |
The University of Washington under the direction of Dr. D.Eugene Strandness |
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These criteria classify ICA lesions into the following ranges of stenosis |
Normal, 1% to 15%, 16% to 49%, 50% to 79%, 80% to 99%, and occlusion |
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Prospective validation of these criteria has demonstrated |
99% sensitivity for the detection of carotid disease and an 84% specificity for the identification of normal arteries |
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Based on a detailed review of multiple Doppler waveform parameters, the best criteria for identifying a 70% or greater internal carotid stenosis, was a |
PSV of two 30 cm/s or greater, or an internal carotid to common carotid PSV ratio of 4.0 or greater |
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Based on a detailed review of multiple Doppler waveform parameters, the best criteria for identifying a 70% or greater internal carotid stenosis, was a |
PSV of two 30 cm/s or greater, or an internal carotid to common carotid PSV ratio of 4.0 or greater |
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When calculating the I CA/CCA ratio it is important to use |
The highest PSV from the stenotic site for the ICA value in the PSV in a normal mid to distal common carotid artery segment for the CCA value |
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The severity of internal carotid stenosis was calculated from arteriograms by |
Comparing the diameter of the minimal residual lumen at the stenotic say to the diameter of the normal distal cervical internal carotid |
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The approach to measuring the stenosis is now often referred to as the |
NASCET method |
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Calculations of and geographic stenosis using the distal internal carotid is the reference vessel results in |
Lower stenosis percentages then calculations using the bulb as a reference site |
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Normal internal carotid artery stenosis |
The ICA PSV is less than 125 cm/s and there is no visible plaque |
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ICA stenosis of less than 50% |
Present when the I CA PSV Is less than 125 cm/s and there’s no visible plaque |
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ICA stenosis of less than 50% |
Present when the I CA PSV Is less than 125 cm/s and there’s no visible plaque |
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ICA stenosis of 50% to 69% is present win |
The ICA PSV Is 125 to 30 cm/s and there is no visible Plaque |
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ICA stenosis greater than 70% to 99% but less than near occlusion is present win |
ICA PSV is more than 230 cm/s and there is visible plaque with lumin narrowing |
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ICA stenosis greater than 70% to 99% but less than near occlusion is present win |
ICA PSV is more than 230 cm/s and there is visible plaque with lumin narrowing |
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Near occlusion of the ICA |
The velocity parameters may not apply |
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Ocollusion |
There is no detectable patent Newman on grayscale imaging and no flow with pulsed doppler |
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The main benefit from using the color Doppler and power Doppler modalities is the |
Rapid identification of flow disturbances and determining the location and direction of high velocity jets |
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Power Doppler is particularly helpful in detecting |
Extremely low flow velocity’s including string sign flow |
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Whenever possible, the color Doppler scale should be set high enough so that |
No color aliasing is present during any phase of the cardiac cycle and low enough so that color feels the patent lumen with even the lowest velocities |
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Color Doppler transmit frequency can be adjusted to provide better |
Resolution or penetration depending on Vessel depth |
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Smooth, single color in the low to medium tone range indicates |
Laminar flow |
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Smooth, single color in the low to medium tone range indicates |
Laminar flow |
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When the flow velocity exceeds the color Doppler scale aliasing occurs |
With brighter tones of color progressing to the opposite Color |
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Turbulent flow produces a typical |
Mosaic Color Doppler pattern |
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Power Doppler modality displays flow based on |
The amplitude of the Doppler signal rather than the frequency shift and us does not give any information on flow direction |
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The main advantage of power Doppler is its ability to |
Detect low flow states |
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Only —— Vertebral artery is usually evaluated during a routine carotid duplex scan |
Proximal |
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Waveform characteristics of vertebral arteries include |
BriskSystolic acceleration, sharp peak, and relatively high diastolic flow |
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A proximal vertebral artery stenosis will produce Abnormal |
Dampened waveforms distally with delayed acceleration, a rounded Peak, and possiblyPost stenotic turbulence |
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Vertebral artery stenosis generally occur at the |
Origin of the vessel from the Subclavian artery |
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A hemodynamically significant stenosis in the proximalSubclavian artery will result in a brachiocephalic pressure gradient of more than |
15 to 20 mmHg |
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Subclavian steel occurs with severe stenosis or occlusion of theSubclavian artery proximal to |
Origin of the vertebral artery |
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Vertebral artery flow direction will be fully retrograde in the case of |
A complete subclavian steel |
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Reactive hyperemia is a |
Noninvasive test that can be used to augment a subclavian steel from the latent to the complete stage |
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Reactive hyperemia testing begins with |
A blood pressure cuff on the upper arm and the cuff is inflated to a pressure that is more than systolic pressure for 3 to 5 minutes and a duplex scan is performed |
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