Duplex/ color flow imaging UE Flashcards
(31 cards)
Localized stenosis
Determine the presence of stenosis
Post - op study: hemodialysis access or arterial bypass graft
Detect AVF’s
Capabilities
Limited access to extremity (dressing, Skin staples, or sutures, open wounds IV site)
Pertaining to hemodialysis access grafts
Limited
Graft angulation
May be difficult to adequately evaluate outflow vein secondary to increased collateral development
Limited
Patient positioning is
Supine
Arm is at 45 degree angle from the body, and externally rotated (pledge position)
Patient positioning
combination of real-time B - mode imaging (gray scale evaluation) and Doppler spectral analysis
Duplex scanning
Doppler information is displayed on image after evaluated for phase (direction toward or away from transducer) and its frequency content (hue or shade of the color)
Doppler color flow imaging
for acquiring pulsed Doppler information
Sample size
usually the sample size is increased by ________ incrementally if needed
1 - 1.5 mm.
What multi frequency transducer is usually utilized?
5-7 MHz linear array transducer
Color duplex scanning is also used to evaluate the following:
Subclavian
Axillary
Brachial
Radial
Ulnar
Palomar Arch (if needed)
For hemodialysis access auscultate the access for?
Bruit and / or “thrill” (vibration)
What is the typical fistula diameter often only
4 or 5 mm.
Inflow Artery
Arterial anastomosis
Continue through the body of the graft
Observe for aneurysm, puncture sites, peri - graft fluid
If color is available, observe the image for flow changes, turbulance
Venous anastomosis
Outflow vein
Evaluate dialysis access grafts
Inflow Artery
Anastomosis (where artery and vein are connected)
outflow vein
Dialysis access fistula assessment sites
Dialysis access examples include:
Brescia - Cimino fistula
straight
looped synthetic grafts
Classic Radial artery to the cephalic vein at wrist
Brescia Cimino dialysis access
Currently no criteria for classifying disease
Normal peak systolic velocities vary widely with skin temperature changes. Doppler signal quality is usually triphasic
suspect a > 50% stenosis? Observe for charactersitiics of the stenosis profile
Stenosis
Observe for lack of Doppler signals (image and or / waveform) and the proverbial “thumb” which is obtained proximal to occlusion
Occlusion
Dilation of the vessel from degeneration and / or weakening of the wall
Aneurysm
Ulnar artery (distal end) aneurysms can form in response to using the palm has a hammer
Hypothenar hammer syndromeS
Subclavian (proximal end) aneurysms often associated with
embolization to the digits
Low PSV obtained in access grafts could indicate
Arterial inflow problems
Peak systolic velocities (PSV) and end diastolic velocities (EDV) vary as to the type of access
Normally both are elevated
Always monophasic and increased velocities
( PSV > 150 cm/sec)