Class 3 (test 2) Flashcards
Carotid color flow exam
Best use of color
Never depend on color alone
Frozen image is temporal color velocities
Best use of color for carotid exam
Identify course of vessels
Identify areas of interest for Doppler
Velocity color shows
Mean velocities
Direction of flow
Course of vessels
Areas to Doppler
Color scale
Start around .3
Avoid aliasing in entire vessel
Set scale to show areas of disturbance
Full vessel wall to wall
Color box
Large size unless fillings an issue
Steer to lowest point, straight for angled vessel
Trans-point towards head to create angle
Appropriate gain-wall to wall. No bleeding
Vertebral color
Ap approach: CCA in long then tilt probe slightly lateral
Decrease scale, increase gain
Vein is superficial to artery
One vert A typically larger with high velocity than other side
When does color mosaic occur
High velocities at stenosis
PRF too low for velocities
Flow disturbance
Power color
Useful to see vessels going different directions
Can’t determine vein from artery (all same color)
Flow separation
Normal at sudden widenings
Laminar flow separates by outer wall and reverses flow
Reasons for color aliasing
Scale too low Low angle High velocities Post stenotic turbulence High velocity around curve
Correcting aliasing in full vessel by
Increasing scale
When there’s no color seen try
Increasing gain
Doppler controls
Long view Steering angle Sample volume size Center stream Gain Doppler angle Scrolling through arteries Samples at correct locations
Measuring carotid velocities
PSV
EDV
ICA/CCA ratio (highest ICA/mid CCA)
Doppler angle
Avoid measuring on curve
Set parallel to walls
Split difference if walls aren’t parallel
Measuring calcified areas
Steer at angle under calcium on both ends
Compare velocities before and after shadow area
Same velocities show normal. Different poss stenosis
ICA Doppler
Low resistance
Diastolic flow above zero except in bulb
EDV higher than ECA
ECA Doppler
High resistance
Diastolic flow near or below zero
EDV lower than ICA
Branches
CCA Doppler
Combo of ICA and ECA
EDV between ICA and ECA
Carotid waveforms
Compare EDV waves
ICA highest
CCA middle
ECA lowest
Use ICA distal to bulb*
ICA waveform
Constant forward flow above baseline
ECA waveform
Often shows notch in downslope
ECA temporal rap
ECA is medial vessel
Find STA pulse by ear, tap STA to check for taps in waveforms
Compare effects of tapping on both sides
Rare
Vertebral techniques
Patient look straight AP approach Find CCA in long Move transducer lateral Vertebral processes (spinal bones)
Vertebral arteries
Decrease color scale and increase gain
Vertebral shadows-picket fence appearance
Deep to vein
Low resistance
Subclavian artery
Best to use distal SCA past clavicle
Use color above clavicle for prox SCA
Doppler waveform
Normally triphasic with higher PSV than CCA
IAC documentation
If you can’t prove it, it doesn’t matter Document normal vs abnormal Color Doppler Protocol Bilateral
Gray scale images minimal
Long of
CCA
bifurcation
ICA
Eileen’s thought of gray scale minimal
Long of M CCA D CCA into ICA D CCA into ECA M&D ICA
IAC minimum Doppler/velocities
P CCA M CCA D CCA P ICA D ICA ECA VERT Abnormal areas
