Podcast
Questions and Answers
What may result in a continuous flow pattern during Doppler venous study?
What may result in a continuous flow pattern during Doppler venous study?
- Pulsatile venous flow
- Thrombosis at the site of examination (correct)
- Reversal of flow during Valsalva
- Distal compression forcing venous blood flow
What does the loss of affect on distal compression during Doppler venous study indicate?
What does the loss of affect on distal compression during Doppler venous study indicate?
- Increased venous velocities
- Arterio-venous fistula
- Venous obstruction from compression site to transducer placement (correct)
- Normal venous blood flow
When does reverse or retrograde flow occur during Doppler venous study?
When does reverse or retrograde flow occur during Doppler venous study?
- With thrombosis at the site of examination
- During proximal vein compression
- With normal venous flow
- Incompetent valves (correct)
Why is angle correction of the Doppler signal not necessary during venous duplex imaging?
Why is angle correction of the Doppler signal not necessary during venous duplex imaging?
What does pulsatile venous flow indicate in Doppler venous study?
What does pulsatile venous flow indicate in Doppler venous study?
What is the purpose of compressions in the transverse view during a venous ultrasound?
What is the purpose of compressions in the transverse view during a venous ultrasound?
What should be done to the Doppler sample volume during Doppler venous study to visualize low-velocity signals?
What should be done to the Doppler sample volume during Doppler venous study to visualize low-velocity signals?
What is the significance of distal augmentation during a venous ultrasound?
What is the significance of distal augmentation during a venous ultrasound?
In which position should the patient be placed for a venous ultrasound to test the response to Valsalva's Maneuver?
In which position should the patient be placed for a venous ultrasound to test the response to Valsalva's Maneuver?
How does phasic flow differ from continuous flow in a venous ultrasound?
How does phasic flow differ from continuous flow in a venous ultrasound?
What happens to the blood flow in veins during Valsalva's Maneuver in a normal response?
What happens to the blood flow in veins during Valsalva's Maneuver in a normal response?
What is the characteristic of normal veins when compressed by a transducer during a venous ultrasound?
What is the characteristic of normal veins when compressed by a transducer during a venous ultrasound?
Study Notes
Patient Positioning
- Patient is positioned in supine position with the leg externally rotated and the knee slightly flexed.
- The bed or table should be in reverse Trendelenburg (head-elevated) position.
Transverse View
- Locate the veins and perform compression maneuver on 2D imaging.
- Normal veins: vessel walls collapse with light to moderate pressure by the transducer on the skin.
- Compressions are done 3cm to 4cm distance in the whole length.
Normal Doppler Signals
- Sagittal view is used.
- Spontaneous flow: flow occurs spontaneously with the patient at rest.
- Phasic flow: follows the respiratory pattern of the patient, with greater flow in lower extremity during expiration and decreased or cessation in flow during inspiration.
- Distal augmentation: manual compression of the extremity distal to the site of ultrasound examination increases or augments venous flow.
- Response to Valsalva's maneuver: normal deep inspiration followed by bearing down results in cessation of blood flow in veins, and increased velocities are seen after completing the Valsalva.
Abnormal Doppler Signals
- Loss of spontaneous flow: loss of respiratory phasicity, continuous flow pattern.
- Loss of effect on distal compression: no increase in venous flow and velocities.
- Reversal of flow during Valsalva or proximal compression: reverse or retrograde flow.
- Pulsatile venous flow: pulsatile flow rather than a smooth phasic flow pattern.
Important Points for Doppler Venous Study
- Doppler signals should be obtained from the longitudinal plane.
- Angle correction of the Doppler signal is not necessary during venous duplex imaging.
- Doppler sample volume may be increased to include the entire lumen of the vein, and the Doppler scale should be reduced to visualize the low-velocity venous Doppler signal.
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Description
Test your knowledge on performing lower extremity venous ultrasound using supine position with leg externally rotated. Learn how to locate veins, perform compression maneuvers, and interpret normal Doppler signals. Practice identifying normal vessel walls collapse and proper transducer pressure.
