A radiation-free examination that displays the direction, velocity and quality of blood flow in arteries and veins using sound waves, with both color and spectral analysis.
Indication
- Suspicion of clot in leg veins (deep vein thrombosis) and superficial vein thrombophlebitis
- Evaluation of varicose vein disease and venous insufficiency
- Screening for stenosis and plaque in carotid and vertebral arteries (stroke risk)
- Peripheral arterial disease; in cases of leg pain, coldness and non-healing wounds
- Renal artery stenosis and evaluation of renal arteries and veins
- Examination of fetal-uteroplacental circulation during pregnancy (obstetric Doppler)
- Evaluation of vascular patterns of masses in the thyroid, testis and intra-abdominal organs
Preparation
- For intra-abdominal vessel studies (aorta, mesenteric, renal artery), 6-8 hours of fasting is generally recommended
- No special preparation is needed for extremity Doppler; comfortable clothing that exposes the area to be examined is preferred
- Limiting smoking and caffeine before the examination may be advised, as they can affect arterial flow
- The patient is allowed to rest for 5-10 minutes at room temperature for warming and vasodilation
How it's performed
- The patient is positioned supine, prone or laterally according to the area to be examined
- Water-based gel is applied to the skin to facilitate transmission of sound waves
- The radiologist or specialist physician follows the vessel course with the probe and acquires B-mode images
- Flow direction and velocity are evaluated on the color map with color Doppler, and as waveforms with spectral Doppler
- In leg veins, compression maneuvers (probe pressure) and the Valsalva maneuver are used to look for reflux and obstruction
- The procedure usually takes 20-45 minutes; this varies according to the area covered
Post-procedure
- When the examination ends, the gel is wiped off with tissue paper and the patient may immediately resume normal activities
- If a clot (DVT) is detected, the physician will inform the patient about starting anticoagulant therapy and bed rest
- Additional tests (CT/MR angiography, catheter angiography) may be planned in carotid stenosis or peripheral arterial disease
- Follow-up Doppler may be requested at intervals during or after treatment for monitoring purposes
Risks
- Doppler ultrasonography does not contain ionizing radiation and has no known invasive side effects
- Mild temporary discomfort due to probe pressure may occur
- Obesity, intestinal gas and tissue thickness may reduce image quality and require repeating the examination
- Accuracy of the examination depends on the operator's experience (operator-dependent)
FAQ
Is Doppler ultrasonography different from MRI or CT?
Doppler does not involve radiation or contrast medium and provides real-time blood flow information. MR and CT angiography offer wider anatomical coverage; Doppler is used as a fast, repeatable and low-cost initial examination.
Is Doppler safe during pregnancy?
Doppler ultrasonography is routinely used in pregnancy to evaluate placental and umbilical cord circulation. When used within indications, it has no known risk.
Does every patient with leg swelling need Doppler?
Unilateral, sudden-onset leg swelling accompanied by redness and pain must be evaluated with Doppler for a clot. The physician decides on testing based on clinical findings and risk scores.
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