AIM:
This investigation is performed to assess the veins of the upper limb for their suitability as bypass grafts, for fistulas and to exclude thrombosis of the vessel or other arteriovenous pathology.
PATIENT PREPARATION:
There are no special instructions for this examination.
STUDY TECHNIQUE:
Patients are required to remove their shirt to enable scanning of the arm veins through the shoulder region and across the base of the neck, undergarments can be left on. Special ultrasound gel is applied to the skin, this is removed at the end of the scan. The gel allows the probe to pass freely across the skin as well improving the image quality. You may be asked to raise or lower the limb depending upon the investigation being performed.
STUDY TIME:
The ultrasound examination will take approximately 20 to 30 minutes.
DIAGNOSTIC CRITERIA:
| B Mode | Doppler | Colour / Power | |
|---|---|---|---|
| Normal | No intraluminal echoes Vein compresses |
Forward flow, phasic, augments |
Colour fills lumen |
| Partial Clot | Some echoes, partially compresses |
May be normal or reduced phasicity |
Defect in colour |
| Thrombosed vessel | Filled with echoes, noncompressible |
No Doppler signal | No colour fill |
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